5y^8-125
*you have to factor completley
easy. Take out the five:
5(y^8-25)
Now, isnt y8 the same as y4 )2 ? That is a square, so you have that y4 squared minus another perfect square? That factor as the difference of two squares. After doing that, you may have another difference of squares to factor.
So would it be 5(y^2-5)