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II2. Suppose f(x, y, z) and g(x, y, z) are continuously differentiable functions with f (1, 2, 3) = 5 and g(1, 2, 3) - 7. Assume that the surface f(x, y, z) = 5 and the surface g(x, y, z) = 7 have the same tangent plane at (1, 2, 3). Evaluate Vf (1, 2, 3) x Vg(1, 2, 3) (remember to give reasons)