Suppose that both (x, y) and the constraint function g(x, y) are linear. Use contour maps to

Suppose that both ƒ(x, y) and the constraint function g(x, y) are linear. Use contour maps to explain why ƒ(x, y) does not have a maximum subject to g(x, y) = 0 unless g = aƒ + b for some constants a, b.