Question

For what values of a and b is each quadrilateral a parallelogram

Answer 1

a = 4

b = 5

Explanation:

In parallelogram, opposite sides are equal and parallel.

therefore 2b + 15 = 5a + b

=> b + 15 = 5a

b = 5a - 15

and 4a + b = 5b - a

=> 5a = 4b

Substitute b = 5a - 15

5a = 4(5a - 15)

5a = 20a - 60

15a = 60

a = 4

b = 5a - 15

b = 5(4) - 15 = 20 - 15 = 5