B) -2 3. Let g(x, y, z) = xyz - x-3y-z - 4. Evaluate A) -1 ag at (1,1,1). C) -3 D) -4 E) -5 4. Compute the directional derivative of the function f(x, y) = xy + 3x at the point (1,2) in the direction (1/2,-1/2). A) 22 B) 32 C) 42 D) 52 E) 62 5. Find an equation of the tangent plane to the surface z = x+2y2 at the point (1,1,3). A) z = x+y+1 E) z=2x+2y-1 B) z = x+2y C) z=2x+4y-3 D) 2=x-2y+4