For what value of x must ABCD be a parallelogram?

Answer:
x = 3
Step-by-step explanation:
to be a parallelogram opposite sides have to be equal
so we have
[tex]DC = AB\\\\20x-7 = 16x+5[/tex]
now solve for x
[tex]20x-7+7 = 16x+5+7\\\\20x = 16x + 12\\\\20-16x = 16x+12-16x\\\\4x = 12\\\\x = \frac{12}{4} = 3[/tex]