I just started studying algebra recently and can't factor this one problem correctly: [(y-1)^4] - (y-1)^2 The answer from the back of the book is y[(y-1)^2](y-2).
But, I can't get it. I know (y-1)^2 = [y^2]-2y+1, which helps to a point. I get as far as [y^4]-[4y^3]+[5y^2]-2y and can't seem to really factor any further. By the way, I added all square brackets just to avoid confusion with the exponents. There are none in the equation.