Hi, I was just doing some review and I'm having trouble with this question, I was wondering if you'd be able to please help me out with it. Thank you in advance.

1. Define the function z = f(I, y) = ery - cy. (a) Show that the points (0, -8) and (1, 0) lie on the same Contour curve of f (1, 7). (b) Suppose that r and y are functions of { as follows: r(t) = m + nt and y(t) = ut. Substitute r(t) = m + nt and y(t) = ut into f (r, y) to obtain a function of the form g(t). Calculate dad de ii. Calculate dalt using the Chain Rule for functions of 2 variables g(t) = f(x(t), y(t)). How does your result compare to the result in part (@)