Solve for x 3^x=40

$3^{x} = 40$

Step 1

Take the natural logarithm of both sides of the equation to remove the variable from the exponent.

$\ln (3^{x}) = \ln (40)$

Step 2

Expand $\ln (3^{x})$ by moving $x$ outside the logarithm.

$x \ln (3) = \ln (40)$

Step 3

Divide each term in $x \ln (3) = \ln (40)$ by $\ln (3)$ and simplify.

Divide each term in $x \ln (3) = \ln (40)$ by $\ln (3)$ .

$\frac{x \ln (3)}{\ln (3)} = \frac{\ln (40)}{\ln (3)}$

Simplify the left side.

Cancel the common factor of $\ln (3)$ .

Cancel the common factor.

$\frac{x \ln (3)}{\ln (3)} = \frac{\ln (40)}{\ln (3)}$

Divide $x$ by $1$ .

$x = \frac{\ln (40)}{\ln (3)}$

Step 4

The result can be shown in multiple forms.

Exact Form:

$x = \frac{\ln (40)}{\ln (3)}$

Decimal Form:

$x = 3.35776278 \dots$