Answer:
x = 9
Step-by-step explanation:
Diagonals of a parallelogram bisect each other. For quadrilateral LMNO to be a parallelogram, LP must equal PN, and OP must equal PM.
Set OP equal to PM and solve for x.
PM = OP
3x - 9 = 18
Add 9 to both sides.
3x = 27
Divide both sides by 3.
x = 9
