3x + 2y = 13
⇒ 2y = 13 - 3x
⇒ y = 1/2 (13-3x)
We know bot x and y are integers. So
if x = 1, y = 5 ---------------first solution
if x = 2, y = 3.5 -------------not a solution
if x=3, y = 2 ----------------second solution.
Since we need only one answer, y = 2
Hope it helps!