Electric potential is given by V=6x-8xy2-8y+6yz-4z2 Then electric force acting on 2C point charge placed on origin will be

Ex=-dVdx=-6-8y2,Ey=-dVdy=-(-16xy-8+6z) Ez=-dVdz=-(6y-8z) At origin, x = y = z = 0  so, Ex=-6,Ey=8 and Ez=0 ⇒E=Ex2+Ey2=10 N/C  Hence, force F=QE=2×10=20 N