Решите уравнение: 3*3^2x - 7*12^x + 4*4^2x = 0

3*(3^2x) - 7*912^x) + 4*04^2x) = 0
3*(3^2x) - 7*(3^x)*(4^x) + 4*(4^2x) = 0  / (4^2x)
3*[(3/4)^2x]  - 7*[(3/4)^x] + 4 = 0
(3/4)^x = z
3*(z^2) - 7z + 4 = 0
D = 49 - 4*3*4 = 1
z1 = (7 - 1)/6
z1 = 1
z2 = (7 +1)/6
z2 = 4/3
1)  (3/4)^x = 1
(3/4)^x = (3/4)^0 
x1 = 0
2) (3/4)^x = 4/3
(3/4)^x = (3/4)^(-1)
x2 = -1