Find the Inverse (-2x-9)/(-6x-7)

$\frac{- 2 x - 9}{- 6 x - 7}$

Step 1

Interchange the variables.

$x = \frac{- 2 y - 9}{- 6 y - 7}$

Step 2

Solve for $y$ .

Rewrite the equation as $\frac{- 2 y - 9}{- 6 y - 7} = x$ .

$\frac{- 2 y - 9}{- 6 y - 7} = x$

Find the LCD of the terms in the equation.

Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.

$- 6 y - 7, 1$

Remove parentheses.

$- 6 y - 7, 1$

The LCM of one and any expression is the expression.

$- 6 y - 7$

Multiply each term in $\frac{- 2 y - 9}{- 6 y - 7} = x$ by $- 6 y - 7$ to eliminate the fractions.

Multiply each term in $\frac{- 2 y - 9}{- 6 y - 7} = x$ by $- 6 y - 7$ .

$\frac{- 2 y - 9}{- 6 y - 7} (- 6 y - 7) = x (- 6 y - 7)$

Simplify the left side.

Multiply $\frac{- 2 y - 9}{- 6 y - 7}$ by $- 6 y - 7$ .

$\frac{(- 2 y - 9) (- 6 y - 7)}{- 6 y - 7} = x (- 6 y - 7)$

Cancel the common factor of $- 6 y - 7$ .

Cancel the common factor.

$\frac{(- 2 y - 9) (- 6 y - 7)}{- 6 y - 7} = x (- 6 y - 7)$

Divide $- 2 y - 9$ by $1$ .

$- 2 y - 9 = x (- 6 y - 7)$

Simplify the right side.

Apply the distributive property.

$- 2 y - 9 = x (- 6 y) + x \cdot - 7$

Reorder.

Rewrite using the commutative property of multiplication.

$- 2 y - 9 = - 6 x y + x \cdot - 7$

Move $- 7$ to the left of $x$ .

$- 2 y - 9 = - 6 x y - 7 x$

Solve the equation.

Add $6 x y$ to both sides of the equation.

$- 2 y - 9 + 6 x y = - 7 x$

Add $9$ to both sides of the equation.

$- 2 y + 6 x y = - 7 x + 9$

Factor $2 y$ out of $- 2 y + 6 x y$ .

Factor $2 y$ out of $- 2 y$ .

$2 y (- 1) + 6 x y = - 7 x + 9$

Factor $2 y$ out of $6 x y$ .

$2 y (- 1) + 2 y (3 x) = - 7 x + 9$

Factor $2 y$ out of $2 y (- 1) + 2 y (3 x)$ .

$2 y (- 1 + 3 x) = - 7 x + 9$

Divide each term in $2 y (- 1 + 3 x) = - 7 x + 9$ by $2 (- 1 + 3 x)$ and simplify.

Divide each term in $2 y (- 1 + 3 x) = - 7 x + 9$ by $2 (- 1 + 3 x)$ .

$\frac{2 y (- 1 + 3 x)}{2 (- 1 + 3 x)} = \frac{- 7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Simplify the left side.

Cancel the common factor of $2$ .

Cancel the common factor.

$\frac{2 y (- 1 + 3 x)}{2 (- 1 + 3 x)} = \frac{- 7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Rewrite the expression.

$\frac{y (- 1 + 3 x)}{- 1 + 3 x} = \frac{- 7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Cancel the common factor of $- 1 + 3 x$ .

Cancel the common factor.

$\frac{y (- 1 + 3 x)}{- 1 + 3 x} = \frac{- 7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Divide $y$ by $1$ .

$y = \frac{- 7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Simplify the right side.

Move the negative in front of the fraction.

$y = - \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Step 3

Replace $y$ with $f^{- 1} (x)$ to show the final answer.

$f^{- 1} (x) = - \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Step 4

Verify if $f^{- 1} (x) = - \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$ is the inverse of $f (x) = \frac{- 2 x - 9}{- 6 x - 7}$ .

To verify the inverse, check if $f^{- 1} (f (x)) = x$ and $f (f^{- 1} (x)) = x$ .

Evaluate $f^{- 1} (f (x))$ .

Set up the composite result function.

$f^{- 1} (f (x))$

Evaluate $f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7})$ by substituting in the value of $f$ into $f^{- 1}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = - \frac{7 (\frac{- 2 x - 9}{- 6 x - 7})}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))} + \frac{9}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Combine the numerators over the common denominator.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- 7 \frac{- 2 x - 9}{- 6 x - 7} + 9}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Simplify each term.

Combine $- 7$ and $\frac{- 2 x - 9}{- 6 x - 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{- 7 (- 2 x - 9)}{- 6 x - 7} + 9}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Move the negative in front of the fraction.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{7 (- 2 x - 9)}{- 6 x - 7} + 9}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

To write $9$ as a fraction with a common denominator, multiply by $\frac{- 6 x - 7}{- 6 x - 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{7 (- 2 x - 9)}{- 6 x - 7} + \frac{9 (- 6 x - 7)}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Combine the numerators over the common denominator.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{- 7 (- 2 x - 9) + 9 (- 6 x - 7)}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Simplify the numerator.

Apply the distributive property.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{- 7 (- 2 x) - 7 \cdot - 9 + 9 (- 6 x - 7)}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply $- 2$ by $- 7$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{14 x - 7 \cdot - 9 + 9 (- 6 x - 7)}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply $- 7$ by $- 9$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{14 x + 63 + 9 (- 6 x - 7)}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Apply the distributive property.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{14 x + 63 + 9 (- 6 x) + 9 \cdot - 7}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply $- 6$ by $9$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{14 x + 63 - 54 x + 9 \cdot - 7}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply $9$ by $- 7$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{14 x + 63 - 54 x - 63}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Subtract $54 x$ from $14 x$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{- 40 x + 63 - 63}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Subtract $63$ from $63$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{- 40 x + 0}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Add $- 40 x$ and $0$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{- 40 x}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Simplify with factoring out.

Move the negative in front of the fraction.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{(40) x}{- 6 x - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Factor $- 1$ out of $- 6 x$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{40 x}{- (6 x) - 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Rewrite $- 7$ as $- 1 (7)$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{40 x}{- (6 x) - 1 \cdot 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Factor $- 1$ out of $- (6 x) - 1 (7)$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{40 x}{- (6 x + 7)}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Simplify the expression.

Rewrite $- (6 x + 7)$ as $- 1 (6 x + 7)$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- \frac{40 x}{- 1 (6 x + 7)}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Move the negative in front of the fraction.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{40 x}{6 x + 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply $- 1$ by $- 1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{1 (\frac{40 x}{6 x + 7})}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply $\frac{40 x}{6 x + 7}$ by $1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{\frac{40 x}{6 x + 7}}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Multiply the numerator by the reciprocal of the denominator.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{40 x}{6 x + 7} \cdot \frac{1}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Simplify terms.

Cancel the common factor of $2$ .

Factor $2$ out of $40 x$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{2 (20 x)}{6 x + 7} \cdot \frac{1}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Cancel the common factor.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{2 (20 x)}{6 x + 7} \cdot \frac{1}{2 (- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7}))}$

Rewrite the expression.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{6 x + 7} \cdot \frac{1}{- 1 + 3 (\frac{- 2 x - 9}{- 6 x - 7})}$

Combine $3$ and $\frac{- 2 x - 9}{- 6 x - 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{6 x + 7} \cdot \frac{1}{- 1 + \frac{3 (- 2 x - 9)}{- 6 x - 7}}$

Multiply $\frac{20 x}{6 x + 7}$ by $\frac{1}{- 1 + \frac{3 (- 2 x - 9)}{- 6 x - 7}}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (- 1 + \frac{3 (- 2 x - 9)}{- 6 x - 7})}$

Simplify the denominator.

To write $- 1$ as a fraction with a common denominator, multiply by $\frac{- 6 x - 7}{- 6 x - 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (- 1 \cdot \frac{- 6 x - 7}{- 6 x - 7} + \frac{3 (- 2 x - 9)}{- 6 x - 7})}$

Combine $- 1$ and $\frac{- 6 x - 7}{- 6 x - 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- (- 6 x - 7)}{- 6 x - 7} + \frac{3 (- 2 x - 9)}{- 6 x - 7})}$

Combine the numerators over the common denominator.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- (- 6 x - 7) + 3 (- 2 x - 9)}{- 6 x - 7})}$

Reorder terms.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{3 (- 2 x - 9) - (- 6 x - 7)}{- 6 x - 7})}$

Rewrite $\frac{3 (- 2 x - 9) - (- 6 x - 7)}{- 6 x - 7}$ in a factored form.

Apply the distributive property.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{3 (- 2 x) + 3 \cdot - 9 - (- 6 x - 7)}{- 6 x - 7})}$

Multiply $- 2$ by $3$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 6 x + 3 \cdot - 9 - (- 6 x - 7)}{- 6 x - 7})}$

Multiply $3$ by $- 9$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 6 x - 27 - (- 6 x - 7)}{- 6 x - 7})}$

Apply the distributive property.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 6 x - 27 - (- 6 x) + 7}{- 6 x - 7})}$

Multiply $- 6$ by $- 1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 6 x - 27 + 6 x + 7}{- 6 x - 7})}$

Multiply $- 1$ by $- 7$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 6 x - 27 + 6 x + 7}{- 6 x - 7})}$

Add $- 6 x$ and $6 x$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{0 - 27 + 7}{- 6 x - 7})}$

Subtract $27$ from $0$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 27 + 7}{- 6 x - 7})}$

Add $- 27$ and $7$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) (\frac{- 20}{- 6 x - 7})}$

Move the negative in front of the fraction.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{(6 x + 7) \cdot (- 1 \frac{20}{- 6 x - 7})}$

Factor out negative.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{20 x}{- (6 x + 7) \frac{20}{- 6 x - 7}}$

Factor $\frac{20}{- 6 x - 7}$ out of $\frac{20 x}{- (6 x + 7) \frac{20}{- 6 x - 7}}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- 6 x - 7}{20} \cdot \frac{20 x}{- (6 x + 7)}$

Cancel the common factor of $20$ .

Factor $20$ out of $20 x$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- 6 x - 7}{20} \cdot \frac{20 (x)}{- (6 x + 7)}$

Cancel the common factor.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{- 6 x - 7}{20} \cdot \frac{20 x}{- (6 x + 7)}$

Rewrite the expression.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = (- 6 x - 7) (\frac{x}{- (6 x + 7)})$

Move the negative in front of the fraction.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = (- 6 x - 7) (- \frac{x}{6 x + 7})$

Apply the distributive property.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = - 6 x (- \frac{x}{6 x + 7}) - 7 (- \frac{x}{6 x + 7})$

Multiply $- 6 x (- \frac{x}{6 x + 7})$ .

Multiply $- 1$ by $- 6$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = 6 x (\frac{x}{6 x + 7}) - 7 (- \frac{x}{6 x + 7})$

Combine $6$ and $\frac{x}{6 x + 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = x (\frac{6 x}{6 x + 7}) - 7 (- \frac{x}{6 x + 7})$

Combine $x$ and $\frac{6 x}{6 x + 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{x (6 x)}{6 x + 7} - 7 (- \frac{x}{6 x + 7})$

Raise $x$ to the power of $1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 (x \cdot x)}{6 x + 7} - 7 (- \frac{x}{6 x + 7})$

Raise $x$ to the power of $1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 (x \cdot x)}{6 x + 7} - 7 (- \frac{x}{6 x + 7})$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 x^{1 + 1}}{6 x + 7} - 7 (- \frac{x}{6 x + 7})$

Add $1$ and $1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 x^{2}}{6 x + 7} - 7 (- \frac{x}{6 x + 7})$

Multiply $- 7 (- \frac{x}{6 x + 7})$ .

Multiply $- 1$ by $- 7$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 x^{2}}{6 x + 7} + 7 (\frac{x}{6 x + 7})$

Combine $7$ and $\frac{x}{6 x + 7}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 x^{2}}{6 x + 7} + \frac{7 x}{6 x + 7}$

Combine the numerators over the common denominator.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{6 x^{2} + 7 x}{6 x + 7}$

Factor $x$ out of $6 x^{2} + 7 x$ .

Factor $x$ out of $6 x^{2}$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{x (6 x) + 7 x}{6 x + 7}$

Factor $x$ out of $7 x$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{x (6 x) + x \cdot 7}{6 x + 7}$

Factor $x$ out of $x (6 x) + x \cdot 7$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{x (6 x + 7)}{6 x + 7}$

Cancel the common factor of $6 x + 7$ .

Cancel the common factor.

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = \frac{x (6 x + 7)}{6 x + 7}$

Divide $x$ by $1$ .

$f^{- 1} (\frac{- 2 x - 9}{- 6 x - 7}) = x$

Evaluate $f (f^{- 1} (x))$ .

Set up the composite result function.

$f (f^{- 1} (x))$

Evaluate $f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)})$ by substituting in the value of $f^{- 1}$ into $f$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- 2 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 9}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Simplify the numerator.

Factor $- 1$ out of $- 2 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 9$ .

Reorder the expression.

Reorder $- 1$ and $3 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- 2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (- 1 + 3 x)}) - 9}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Reorder $- 1$ and $3 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- 2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)}) - 9}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Factor $- 1$ out of $- 2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})) - 9}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Rewrite $- 9$ as $- 1 (9)$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})) - 1 \cdot 9}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Factor $- 1$ out of $- (2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})) - 1 (9)$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (2 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)}) + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Apply the distributive property.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (2 (- \frac{7 x}{2 (3 x - 1)}) + 2 (\frac{9}{2 (3 x - 1)}) + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Cancel the common factor of $2$ .

Move the leading negative in $- \frac{7 x}{2 (3 x - 1)}$ into the numerator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (2 (\frac{- 7 x}{2 (3 x - 1)}) + 2 (\frac{9}{2 (3 x - 1)}) + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Cancel the common factor.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (2 (\frac{- 7 x}{2 (3 x - 1)}) + 2 (\frac{9}{2 (3 x - 1)}) + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Rewrite the expression.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (\frac{- 7 x}{3 x - 1} + 2 (\frac{9}{2 (3 x - 1)}) + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Cancel the common factor of $2$ .

Cancel the common factor.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (\frac{- 7 x}{3 x - 1} + 2 (\frac{9}{2 (3 x - 1)}) + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Rewrite the expression.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (\frac{- 7 x}{3 x - 1} + \frac{9}{3 x - 1} + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Combine the numerators over the common denominator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (\frac{- 7 x + 9}{3 x - 1} + 9)}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

To write $9$ as a fraction with a common denominator, multiply by $\frac{3 x - 1}{3 x - 1}$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- (\frac{- 7 x + 9}{3 x - 1} + \frac{9 (3 x - 1)}{3 x - 1})}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Combine the numerators over the common denominator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{- 7 x + 9 + 9 (3 x - 1)}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Reorder terms.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{- 7 x + 9 (3 x - 1) + 9}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Rewrite $\frac{- 7 x + 9 (3 x - 1) + 9}{3 x - 1}$ in a factored form.

Apply the distributive property.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{- 7 x + 9 (3 x) + 9 \cdot - 1 + 9}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Multiply $3$ by $9$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{- 7 x + 27 x + 9 \cdot - 1 + 9}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Multiply $9$ by $- 1$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{- 7 x + 27 x - 9 + 9}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Add $- 7 x$ and $27 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x - 9 + 9}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Add $- 9$ and $9$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x + 0}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Add $20 x$ and $0$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Simplify the denominator.

Factor $- 1$ out of $- 6 (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) - 7$ .

Reorder the expression.

Reorder $- 1$ and $3 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- 6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (- 1 + 3 x)}) - 7}$

Reorder $- 1$ and $3 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- 6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)}) - 7}$

Factor $- 1$ out of $- 6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})) - 7}$

Rewrite $- 7$ as $- 1 (7)$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})) - 1 \cdot 7}$

Factor $- 1$ out of $- (6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)})) - 1 (7)$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (6 (- \frac{7 x}{2 (3 x - 1)} + \frac{9}{2 (3 x - 1)}) + 7)}$

Apply the distributive property.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (6 (- \frac{7 x}{2 (3 x - 1)}) + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Cancel the common factor of $2$ .

Move the leading negative in $- \frac{7 x}{2 (3 x - 1)}$ into the numerator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (6 (\frac{- 7 x}{2 (3 x - 1)}) + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Factor $2$ out of $6$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (2 (3) (\frac{- 7 x}{2 (3 x - 1)}) + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Cancel the common factor.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (2 \cdot (3 (\frac{- 7 x}{2 (3 x - 1)})) + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Rewrite the expression.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (3 (\frac{- 7 x}{3 x - 1}) + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Combine $3$ and $\frac{- 7 x}{3 x - 1}$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{3 (- 7 x)}{3 x - 1} + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Multiply $- 7$ by $3$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x}{3 x - 1} + 6 (\frac{9}{2 (3 x - 1)}) + 7)}$

Cancel the common factor of $2$ .

Factor $2$ out of $6$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x}{3 x - 1} + 2 (3) (\frac{9}{2 (3 x - 1)}) + 7)}$

Cancel the common factor.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x}{3 x - 1} + 2 \cdot (3 (\frac{9}{2 (3 x - 1)})) + 7)}$

Rewrite the expression.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x}{3 x - 1} + 3 (\frac{9}{3 x - 1}) + 7)}$

Combine $3$ and $\frac{9}{3 x - 1}$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x}{3 x - 1} + \frac{3 \cdot 9}{3 x - 1} + 7)}$

Multiply $3$ by $9$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x}{3 x - 1} + \frac{27}{3 x - 1} + 7)}$

Combine the numerators over the common denominator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{- 21 x + 27}{3 x - 1} + 7)}$

Factor $3$ out of $- 21 x + 27$ .

Factor $3$ out of $- 21 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{3 (- 7 x) + 27}{3 x - 1} + 7)}$

Factor $3$ out of $27$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{3 (- 7 x) + 3 (9)}{3 x - 1} + 7)}$

Factor $3$ out of $3 (- 7 x) + 3 (9)$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{3 (- 7 x + 9)}{3 x - 1} + 7)}$

To write $7$ as a fraction with a common denominator, multiply by $\frac{3 x - 1}{3 x - 1}$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- (\frac{3 (- 7 x + 9)}{3 x - 1} + \frac{7 (3 x - 1)}{3 x - 1})}$

Combine the numerators over the common denominator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{3 (- 7 x + 9) + 7 (3 x - 1)}{3 x - 1}}$

Reorder terms.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{7 (3 x - 1) + 3 (- 7 x + 9)}{3 x - 1}}$

Rewrite $\frac{7 (3 x - 1) + 3 (- 7 x + 9)}{3 x - 1}$ in a factored form.

Apply the distributive property.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{7 (3 x) + 7 \cdot - 1 + 3 (- 7 x + 9)}{3 x - 1}}$

Multiply $3$ by $7$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{21 x + 7 \cdot - 1 + 3 (- 7 x + 9)}{3 x - 1}}$

Multiply $7$ by $- 1$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{21 x - 7 + 3 (- 7 x + 9)}{3 x - 1}}$

Apply the distributive property.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{21 x - 7 + 3 (- 7 x) + 3 \cdot 9}{3 x - 1}}$

Multiply $- 7$ by $3$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{21 x - 7 - 21 x + 3 \cdot 9}{3 x - 1}}$

Multiply $3$ by $9$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{21 x - 7 - 21 x + 27}{3 x - 1}}$

Subtract $21 x$ from $21 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{0 - 7 + 27}{3 x - 1}}$

Subtract $7$ from $0$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{- 7 + 27}{3 x - 1}}$

Add $- 7$ and $27$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{- \frac{20 x}{3 x - 1}}{- \frac{20}{3 x - 1}}$

Dividing two negative values results in a positive value.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{\frac{20 x}{3 x - 1}}{\frac{20}{3 x - 1}}$

Multiply the numerator by the reciprocal of the denominator.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{20 x}{3 x - 1} \cdot \frac{3 x - 1}{20}$

Cancel the common factor of $20$ .

Factor $20$ out of $20 x$ .

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{20 (x)}{3 x - 1} \cdot \frac{3 x - 1}{20}$

Cancel the common factor.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{20 x}{3 x - 1} \cdot \frac{3 x - 1}{20}$

Rewrite the expression.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{x}{3 x - 1} \cdot (3 x - 1)$

Cancel the common factor of $3 x - 1$ .

Cancel the common factor.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = \frac{x}{3 x - 1} \cdot (3 x - 1)$

Rewrite the expression.

$f (- \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}) = x$

Since $f^{- 1} (f (x)) = x$ and $f (f^{- 1} (x)) = x$ , then $f^{- 1} (x) = - \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$ is the inverse of $f (x) = \frac{- 2 x - 9}{- 6 x - 7}$ .

$f^{- 1} (x) = - \frac{7 x}{2 (- 1 + 3 x)} + \frac{9}{2 (- 1 + 3 x)}$

Find the Inverse (-2x-9)/(-6x-7)

Related Questions

Support LCMGCF.com by disabling your adblocker.