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
