for what values of a and b is each quadrilateral a parallelogram?

Left: 4a+b
Top: 2b+15
Right: 5b-a
Bottom: 5a+b

1 answer

One of the properties of a parallelogram
opposite are Always equal

5a+b=2b+15

5a-b=15....(1)

5b-a=4a+b

4b=5a.....(2)

b=5a/4...(3)

Plug into 1

5a-(5a/4)=15....(1)
20a-5a=60

4a-a=12

3a=12

a=4

Now find b