How do I find the potential y values for 32y^3-168y+100=0 It's a multi-variable calc problem. I have to find the critical points of the surface f(x,y) = 10yx^2 - 5x^2 - 4y^2-x^4-2y^4 ∂f/∂x = 20xy-10x-4x^3 = 0 x=0 or x^2 = (20y-10)/4 ∂f/∂y = 8y^3+8y-10x^2=0 I subbed x^2 in and got 32y^3-168y+100=0 Any ideas what I'm doing wrong if I am? Or do I have to find the y values that satisfy 32y^3-168y+100=0? Thanks for reading, guys. Edit: Just realized I should've posted this in the homework help section. Don't know how to delete. Mod could you move this for me?