Question

For what values of a and b is the quadrilateral a parallelogram?

Answer 1

a = 3, b = 10

Explanation:

Opposite sides of a parallelogram are equal, so:
3a + 1 = b
5a = 2b - 5
Substituting 3a + 1 = b in the second equation,
5a = 2(3a + 1) - 5
= 6a + 2 -5
= 6a -3
6a - 5a = 3
So, a = 3
Now, 3a + 1 = b
So, b = 3(3) + 1
= 9 + 1
= 10