Please help me with this question solving for x. Thanks.

4^x = 10 - 4^(x + 1)

It's easier if you let u=4^x. Then

4^(x+1) = 4*4^x = 4u and you have

u = 10-4u
5u=10
u=2
4^x = 2
but, 2 = √4 = 4^(1/2), so
x = 1/2