Answer:
x= -4
Step-by-step explanation:
∠LMP + ∠PMN= 180° (adj. ∠s on a str. line)
-16x +13 -20x +23= 180
bring x term to 1 side, constant to the other:
-36x= 180 -13 -23
Simplify:
-36x= 144
x= 144 ÷ (-36)
x= -4
*The sum of the angles on a straight line is 180°