If 4^x = 3, what is 4^2x-2
4^x = 3 ⇒ (4^x)^2 = 3^2 ⇒ (4^x)^2 = 9
So....
4^(2x - 2) =
(4^2)^(x - 1) =
( 4^2)^x / (4^2) =
(4^x)^2 / ( 16) =
9 / 16