5. Let f(x, y) = x2 - 3. Label all axes. Label all curves with the appropriate values to distinguish them. a. Sketch the sections z = f(a, y), in the planes x = a for a = 0 and 1. b. Sketch the sections z = f(x, b), in the planes y = b for b = 0 and 1. c. Sketch the contour curves (implicit graphs) f(x, y) = c for c =0 and 1. d. Sketch the explicit graph of z = f(x, y). Describe it in words if you can't draw it