1) (y-2)^2 - 4(y-2) = (y-2) ((y-2) - 4) = (y-2) (y-6)
2) (x+7)^2 - 9(x+7) = (x+7) ((x+7) - 9) = (x+7) (x-2)
3) (x-5)^2 - 8(x-5) = (x-5) ((x-5) - 8) = (x-5) (x-13)
