4^x-1=64

Answer 1

Did you mean?:
4^x -1 = 64
4^x = 63
x log(4) = log(63)
x = log(63)/log(4)

Or did you mean?:
4^(x-1) = 64
4^(x-1) = 4^3
x = 2

Answer 2

thanks i got 2, too.

5^x + 10 = 15