Find the Inverse x/(x-20)

$\frac{x}{x - 20}$

Step 1

Interchange the variables.

$x = \frac{y}{y - 20}$

Step 2

Solve for $y$ .

Multiply the equation by $y - 20$ .

$(y - 20) (x) = (\frac{y}{y - 20}) (y - 20)$

Simplify the left side.

Apply the distributive property.

$y x - 20 x = (\frac{y}{y - 20}) (y - 20)$

Simplify the right side.

Cancel the common factor of $y - 20$ .

Cancel the common factor.

$y x - 20 x = \frac{y}{y - 20} (y - 20)$

Rewrite the expression.

$y x - 20 x = y$

Solve for $y$ .

Subtract $y$ from both sides of the equation.

$y x - 20 x - y = 0$

Add $20 x$ to both sides of the equation.

$y x - y = 20 x$

Factor $y$ out of $y x - y$ .

Factor $y$ out of $y x$ .

$y (x) - y = 20 x$

Factor $y$ out of $- y$ .

$y (x) + y \cdot - 1 = 20 x$

Factor $y$ out of $y (x) + y \cdot - 1$ .

$y (x - 1) = 20 x$

Divide each term in $y (x - 1) = 20 x$ by $x - 1$ and simplify.

Divide each term in $y (x - 1) = 20 x$ by $x - 1$ .

$\frac{y (x - 1)}{x - 1} = \frac{20 x}{x - 1}$

Simplify the left side.

Cancel the common factor of $x - 1$ .

Cancel the common factor.

$\frac{y (x - 1)}{x - 1} = \frac{20 x}{x - 1}$

Divide $y$ by $1$ .

$y = \frac{20 x}{x - 1}$

Step 3

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

$f^{- 1} (x) = \frac{20 x}{x - 1}$

Step 4

Verify if $f^{- 1} (x) = \frac{20 x}{x - 1}$ is the inverse of $f (x) = \frac{x}{x - 20}$ .

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 $f^{- 1} (\frac{x}{x - 20})$ by substituting in the value of $f$ into $f^{- 1}$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{20 (\frac{x}{x - 20})}{(\frac{x}{x - 20}) - 1}$

Combine $20$ and $\frac{x}{x - 20}$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{x}{x - 20} - 1}$

Simplify the denominator.

To write $- 1$ as a fraction with a common denominator, multiply by $\frac{x - 20}{x - 20}$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{x}{x - 20} - 1 \cdot \frac{x - 20}{x - 20}}$

Combine $- 1$ and $\frac{x - 20}{x - 20}$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{x}{x - 20} + \frac{- (x - 20)}{x - 20}}$

Combine the numerators over the common denominator.

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{x - (x - 20)}{x - 20}}$

Rewrite $\frac{x - (x - 20)}{x - 20}$ in a factored form.

Apply the distributive property.

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{x - x + 20}{x - 20}}$

Multiply $- 1$ by $- 20$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{x - x + 20}{x - 20}}$

Subtract $x$ from $x$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{0 + 20}{x - 20}}$

Add $0$ and $20$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{\frac{20 x}{x - 20}}{\frac{20}{x - 20}}$

Multiply the numerator by the reciprocal of the denominator.

$f^{- 1} (\frac{x}{x - 20}) = \frac{20 x}{x - 20} \cdot \frac{x - 20}{20}$

Cancel the common factor of $20$ .

Factor $20$ out of $20 x$ .

$f^{- 1} (\frac{x}{x - 20}) = \frac{20 (x)}{x - 20} \cdot \frac{x - 20}{20}$

Cancel the common factor.

$f^{- 1} (\frac{x}{x - 20}) = \frac{20 x}{x - 20} \cdot \frac{x - 20}{20}$

Rewrite the expression.

$f^{- 1} (\frac{x}{x - 20}) = \frac{x}{x - 20} \cdot (x - 20)$

Cancel the common factor of $x - 20$ .

Cancel the common factor.

$f^{- 1} (\frac{x}{x - 20}) = \frac{x}{x - 20} \cdot (x - 20)$

Rewrite the expression.

$f^{- 1} (\frac{x}{x - 20}) = x$

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

Set up the composite result function.

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

Evaluate $f (\frac{20 x}{x - 1})$ by substituting in the value of $f^{- 1}$ into $f$ .

$f (\frac{20 x}{x - 1}) = \frac{\frac{20 x}{x - 1}}{(\frac{20 x}{x - 1}) - 20}$

Multiply the numerator by the reciprocal of the denominator.

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 x}{x - 1} - 20}$

Simplify the denominator.

To write $- 20$ as a fraction with a common denominator, multiply by $\frac{x - 1}{x - 1}$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 x}{x - 1} - 20 \cdot \frac{x - 1}{x - 1}}$

Combine $- 20$ and $\frac{x - 1}{x - 1}$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 x}{x - 1} + \frac{- 20 (x - 1)}{x - 1}}$

Combine the numerators over the common denominator.

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 x - 20 (x - 1)}{x - 1}}$

Rewrite $\frac{20 x - 20 (x - 1)}{x - 1}$ in a factored form.

Factor $20$ out of $20 x - 20 (x - 1)$ .

Factor $20$ out of $20 x$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 (x) - 20 (x - 1)}{x - 1}}$

Factor $20$ out of $- 20 (x - 1)$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 (x) + 20 (- (x - 1))}{x - 1}}$

Factor $20$ out of $20 (x) + 20 (- (x - 1))$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 (x - (x - 1))}{x - 1}}$

Apply the distributive property.

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 (x - x + 1)}{x - 1}}$

Multiply $- 1$ by $- 1$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 (x - x + 1)}{x - 1}}$

Subtract $x$ from $x$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 (0 + 1)}{x - 1}}$

Add $0$ and $1$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20 \cdot 1}{x - 1}}$

Multiply $20$ by $1$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{1}{\frac{20}{x - 1}}$

Multiply the numerator by the reciprocal of the denominator.

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot (1 (\frac{x - 1}{20}))$

Multiply $\frac{x - 1}{20}$ by $1$ .

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{x - 1}{20}$

Cancel the common factor of $20$ .

Factor $20$ out of $20 x$ .

$f (\frac{20 x}{x - 1}) = \frac{20 (x)}{x - 1} \cdot \frac{x - 1}{20}$

Cancel the common factor.

$f (\frac{20 x}{x - 1}) = \frac{20 x}{x - 1} \cdot \frac{x - 1}{20}$

Rewrite the expression.

$f (\frac{20 x}{x - 1}) = \frac{x}{x - 1} \cdot (x - 1)$

Cancel the common factor of $x - 1$ .

Cancel the common factor.

$f (\frac{20 x}{x - 1}) = \frac{x}{x - 1} \cdot (x - 1)$

Rewrite the expression.

$f (\frac{20 x}{x - 1}) = x$

Since $f^{- 1} (f (x)) = x$ and $f (f^{- 1} (x)) = x$ , then $f^{- 1} (x) = \frac{20 x}{x - 1}$ is the inverse of $f (x) = \frac{x}{x - 20}$ .

$f^{- 1} (x) = \frac{20 x}{x - 1}$

Find the Inverse x/(x-20)

Related Questions

Support LCMGCF.com by disabling your adblocker.