6. Consider the surface implicitly defined by the equation a + y + z - exyz = 0. (a) (1 credit Find an equation for the plane tangent to this surface at the point (0, 0, 1). You may find it useful to know that if F(x, y, z) = x ty+ z -exyz, then VF (x, y, z ) = (1 - yzer yz, 1 - xze" yz, 1 - xye "yz)