Question

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

Explanation:

Step1: Substitute $y=2^x$

$y^2 - y - 12 = 0$

Step2: Factor quadratic equation

$(y-4)(y+3)=0$

Step3: Solve for $y$

$y=4$ (since $y=2^x>0$, discard $y=-3$)

Step4: Find $x$ from $2^x=4$

$x=\log_2 4=2$

Answer:

$\log_2 4$ (or $2$)