Question 590926
Solve the following exponential equation:

2^(2x) + 2^(x+2) - 12 = 0
2^(2x) + 2^x*2^2 - 12 = 0
2^(2x) + 2^x*4 - 12 = 0
2^2x + 4*2^x - 12 = 0
.
let u=2^x
u^2=2^2x
..
u^2+4u-12=0
(u+6)(u-2)=0
u=-6=2^x
no real solution, (2^x>0)
or
u=2=2^x
x=1