1) Consider the following. w = yz/x, x = 0, y = r +70, z = r - 70 (a) Find aw/ar and aw/ae by using the appropriate Chain Rule. aw ar aw 20 (b) Find aw/ar and aw/20 by converting w to a function of rand before differentiating. aw r aw de = 2) Evaluate fx, fy and fz at the given point. +7xyz - 5yz, (-1, 2, 1) f(x, y, z)=xy3 + fx-1, 2, 1) fyl-1, 2, 1) = = 3) For f(x, y), find all values of x and y such that fx(x, y) = 0 and fy(x, y) = 0 simultaneously. f(x, y) = x + 4xy + y2 - 18x-12y + 14 (x, y) =