Joshi sir comment
use kirchhoff laws
4-10i+1-30x = 0
1-30x+20(i-x) = 0
solve it for i and x
potential across A and B = 4-10i+1 = 30x
use kirchhoff laws
4-10i+1-30x = 0
1-30x+20(i-x) = 0
solve it for i and x
potential across A and B = 4-10i+1 = 30x