joshuagates613 joshuagates613 Today at 10:43 PM Mathematics Answered Quadrilateral ABCD is a parallelogram if one pair of opposite sides is both equal and parallel. Prove that Quadrilateral ABCD is a parallelogram by finding the value of x. A) x = -3 B) x = -5 C) x = -7 D) x = - 17 3