Answer:
a = 2, b = 3
Explanation:
The opposite sides of a parallelogram are congruent , so
3a + 11 = a + 15 ( subtract a from both sides )
2a + 11 = 15 ( subtract 11 from both sides )
2a = 4 ( divide both sides by 2 )
a = 2
and
3b + 5 = b + 11 ( subtract b from both sides )
2b + 5 = 11 ( subtract 5 from both sides )
2b = 6 ( divide both sides by 2 )
b = 3