I keep getting stuck on one part of the equation. can somebody help? dy/dx = y(xy3 - 1) dy/dx = xy4 - y dy/dx + y = xy4 u = y1-n = y-3 y = u-3 dy/dx = dy/du * du/dx dy/dx = -3u-4 du/dx Substituting terms into the original equation -3u-4 du/dx + u-3 = x(u-3)4 Here is where I get stuck. When I divide u-4 to clean up the equation, the right hand side still has u-8 remaining. I will not be able to go on since the right hand side can only have x terms. What am I doing wrong?