Question

Find the value of x and y in the parallelogram below.
90
144
-10x+10
-2y-6

Answer 1

In a parallelogram opposite sides are equal, so set each algebraic side equal to its opposite:

90 = -10x + 10
144 = -2y - 6

Solve the first: 90 − 10 = −10x ⇒ 80 = −10x ⇒ x = −8.
Solve the second: 144 + 6 = −2y ⇒ 150 = −2y ⇒ y = −75.

Check: −10(−8)+10 = 90 and −2(−75)−6 = 144.

Answer: x = −8, y = −75.