Solve for x 3^(-x)=3^(3x+6)

$3^{- x} = 3^{3 x + 6}$

Step 1

Create equivalent expressions in the equation that all have equal bases.

$3^{- x} = 3^{3 x + 6}$

Step 2

Since the bases are the same, then two expressions are only equal if the exponents are also equal.

$- x = 3 x + 6$

Step 3

Solve for $x$ .

Move all terms containing $x$ to the left side of the equation.

Subtract $3 x$ from both sides of the equation.

$- x - 3 x = 6$

Subtract $3 x$ from $- x$ .

$- 4 x = 6$

Divide each term in $- 4 x = 6$ by $- 4$ and simplify.

Divide each term in $- 4 x = 6$ by $- 4$ .

$\frac{- 4 x}{- 4} = \frac{6}{- 4}$

Simplify the left side.

Cancel the common factor of $- 4$ .

Cancel the common factor.

$\frac{- 4 x}{- 4} = \frac{6}{- 4}$

Divide $x$ by $1$ .

$x = \frac{6}{- 4}$

Simplify the right side.

Cancel the common factor of $6$ and $- 4$ .

Factor $2$ out of $6$ .

$x = \frac{2 (3)}{- 4}$

Cancel the common factors.

Factor $2$ out of $- 4$ .

$x = \frac{2 \cdot 3}{2 \cdot - 2}$

Cancel the common factor.

$x = \frac{2 \cdot 3}{2 \cdot - 2}$

Rewrite the expression.

$x = \frac{3}{- 2}$

Move the negative in front of the fraction.

$x = - \frac{3}{2}$

Step 4

The result can be shown in multiple forms.

Exact Form:

$x = - \frac{3}{2}$

Decimal Form:

$x = - 1.5$

Mixed Number Form:

$x = - 1 \frac{1}{2}$