A function is defined implicitly by x3 + 2xy + y4 = 61 Verify that the point (-2, 3) lies on this...

A function is defined implicitly by x3 + 2xy + y4 = 61 Verify that the point (−2, 3) lies on this curve and find the gradient at this point. (b) Find and classify the stationary point on the surface defined by z = 4x2 − xy + 3y2 − 8x + y + 3