Let f be the linear function f(x, y) = c + mx + ny, where c, m, n are constants and n notequalto 0. (a)Find and expand the equation of the contour that goes through the value f(x, y) = k. y = (b)Note that your equation is a line. What is the slope of the line? slope = (c)Now suppose that we look at the point (x, y) = (2,5). Find and simplify f(2,5):f(2,5) = Find and simplify f(2 + n, 5 - m): f(2 + n, 5 - m) = (d) What do you notice about your result in (c)? Confirm that this works in general by calculating f (x + m, y - n) for any x and y (simplify your expression by expanding out terms): f(x + n, y-m) = Finally, be sure that you can explain how this last result is related the the equation of the line and slope that you found in (a) and (b).