The electric field [tex]\mathbf E[/tex] is the negative of the gradient of the electric potential:
[tex]\mathbf E=-\nabla V(x,y,z)=-\left(6xy^2-2z^3,6x^2y+z^3,3yz^2-6xz^2\right)[/tex]
At the point (1.0, 1.0, 1.0), the electric field has magnitude
[tex]\|\mathbf E\|=\|(4.0,7.0,-3.0)\|=8.6\dfrac{\rm V}{\rm m}[/tex]