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

9514 1404 393
Answer:
x= 5
Step-by-step explanation:
Sides BC and AD will be parallel when the two marked angles have the same measure:
5x -3 = 14x -48
45 = 9x . . . . . . . . . add 48-5x
5 = x . . . . . . divide by 9