1. The problem statement, all variables and given/known data\ Find the critical points of the function. Then use the Second Derivative Test to classify each critical point (or state that the test fails). f(x, y) = x3 + y4 - 21x - 18y2 3. The attempt at a solution partial x derivative=3x^2-21=0 partial y= 4y^3-36y=0 i try to solve those for numbers, but the answer space in the question has space for 6 different critical point answers, so I am not sure where to go from here.