I know how to solve by substituting in some instances. The only times I've done it is with examples like this (x +1)^2/3 = (x + 1)^1/3

With this problem since (x+1)^2/3 is [(x+1)^1/3]^2 you can just substitute "u" for the whole thing leaving you with u^2 = u. You would then bring everything to one side and solve the equation from there.

The problem I'm having trouble with though looks a bit different.

(x-3)^2/5 = (4x)^1/5

Now the exponent 2/5 is the square of the exponent 1/5 but x-3 & 4x don't match so you shouldn't be able to just replace them with u.

Anyone know where I should start?