Electrostatic Potential and Capacitance question for JEE Main (JEE Main 2019 (8 Apr, Shift 2)), with solution

The electric field in a region is given by $\vec E = (Ax + B)\hat i$, where $E$ is in $\text{N C}^{-1}$ and $x$ is in metres. The values of constants are $A = 20$ SI unit and $B = 10$ SI unit. If the potential at $x = 1$ is $V_1$ and that at $x = -5$ is $V_2$, then $V_1 - V_2$ is