Question

Find the value of x for which ABCD must be a parallelogram.

Answer 1

parallelogram, opposite sides are equal
so
5x - 8 = 2x + 7
3x = 15
x = 5

Answer 2

x = 5

Explanation:

Property of a parallelogram says that opposite sides of the parallelogram are equal and parallel to each other.

Therefore, BC = AD

(5x - 8) = (2x + 7)

(5x - 8) - 2x = (2x + 7) - 2x

(5x - 2x) - 8 = (2x - 2x) + 7

3x - 8 = 7

(3x - 8) + 8 = 7 + 8

3x = 15

x = 5

Therefore, x = 5 is the answer.