# Exponential Equation (college algebra)

I'm having trouble solving the following equation

$$2^{2x}+2^x-12=0$$

I think maybe I'm suppose to take $\log_2$ perhaps.... not seeing anything poping out.

• Write $2^{2x}$ as $(2^x)^2$. Do you see a quadratic equation? – imranfat Dec 3 '16 at 3:54
• $2^{2x}+2^x-12=(2^x+4)(2^x-3)$. – Michael Hoppe Dec 3 '16 at 12:01
• Why was this downvoted? – Clclstdnt Dec 4 '16 at 18:02

## 1 Answer

\begin{align} & (2^x)^2 + 2^x - 12 = 0 \\[10pt] & u^2+u-12 = 0 \end{align} Solve for $u$, then figure out what $x$ is if $u = 2^x$. Recall that $2^x$ must be positive, so discard any negative values of $u$.

• duh. Forgot that. Thanks – Clclstdnt Dec 3 '16 at 3:59