$\displaystyle F = ( y - z + 2)i +(yz +4)j -xzk$, where S is the surface of the cube $\displaystyle x = 0, y = 0, z = 0, x = 2, y = 2, z = 2$, above the xy plane

So i have computed $\displaystyle \nabla x F = -yi + (-1+z)j -k$ now i dont know what to do next