(2x+3)^(1/2)=4
(5x-5)^(2/3)=16
you want to get the exponent involving x to be 1. So, raise both sides to a power that is the reciprocal of what you have.
(2x+3)^(1/2)=4
2x+3 = 4^2 = 16
x = 13/2
(5x-5)^(2/3)=16
5x-5 = 16^(3/2) = 64
x = 69/5