3(4^x)-2^(x+2) = -1

3(4^x)-2^(x+2) = -1

3(2^2)^x - (2^x)(2^2) + 1 = 0
3(2^x)^2 - 4(2^x) + 1 = 0
let 2^x = m

3n^2 - 4m + 1 = 0
(3m - 1)(m - 1) = 0
m = 1/3 or m = 1

so 2^x = 1/3
x = ln(1/3)/ln2 = appr. -1.585

or

2^x = 1
x = 0