Answer:
x = 5 (check the diagram included)
Explanation:
The question is incomplete, I have included a diagram to aid the understanding of the question
Parallelograms are quadrilaterals which have their opposite sides parallel and equal. This also means that the opposite angles in a parallelogram are equal
From the attached figure, we have:
|FG| = 3x + 10, |HE| = 7x - 30
To calculate for the value of x that makes the quadrilateral a parallelogram, we have:
Remember the opposite sides of a parallelogram are equal
3x + 10 = 7x - 30
3x - 7x = 10 - 30
-4x = -20
x = 20 ÷ 4
x = 5
x = 5 makes the quadrilateral a parallelogram