Question: Suppose that z is a linear function of x and y with slope 2 in the x-direction and slope 3 in the y-direction.
(a) A change of 0.5 in x and -0.2 in y produces what change in z?
(b) If z = 2 when x = 5 and y = 7, what is the value of z when x = 4.9 and y = 7.2?