text: how do you factor 40y3 - 5y4 +15xy?   basically you want to take out everything that is common to all terms(basically a factor common to each term)  there is a multiple of 5 in each term and a y in each term, so you pull those out and divide all of the terms by 5y  so   5y(8y2 - y^3 +3x)  hope this helps!!