Solving for unit’s place,

B + 7 = A

Solving for ten’s place,

A + 3 = 9

∴ A = 6 and B = -1 which is not possible.

Hence, there is one carry in ten’s place, which means B + 7 >9

∴ now solving for ten’s place with one carry,

A +3 +1 = 9

∴ A = 5

For unit’s place subtracting 10 as one carry is given to ten’s place ,

B + 7 - 10= 5

∴ B = 8

Hence, A = 5 and B = 8