please help

Assume that x and y are both differentiable functions of t and find the required values of dy/dt and dx/dt. x2 + y2 = 400 (a) Find dy/dt, given x = 12, y = 16, and dx/dt = 5. dy/dt = (b) Find dx/dt, given x = 16, y = 12, and dy/dt = -4. dx/dt =