Step-by-step explanation:
2^(2x) - 5(2^x) = -4
(2^x)^2 - 5(2^x) = -4
Substitute 2^x = z --> x = ln(z)/ln(2)
z^2 - 5z = -4
z^2 - 5z + 4 = 0
(z - 1)(z - 4) = 0
z = 1 --> x = ln(1)/ln(2) = 0
z = 4 --> x = ln(4)/ln(2) = 2
