1. Given the function z = f(x,y) = -x + 4xy - 3xy? +8 a. Find the directional derivatives at the domain point (Xo yo) =(2,1) in the directions of the vectors -4,-3 > and w=<5,1>. Clearly show all the key steps to produce the results! (5) b. What is the highest value of the directional derivative for this function at this domain point? In what direction in the domain plane does it occur? (2) c. What are the directions of the function's level contour at this location and what is its value? (2) c. What are the directions of the function's level contour at this location and what is its value? (2) d. Plot the key information from parts b&c in the xy-plane provided above (2).