Suppose that both (x, y) and the constraint function g(x, y) are linear. Use contour maps to explain why (x, y) does not have a

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.