Answer:
x = -4
m<LMP = 77°
m<NMP = 103°
Explanation:
Straight angles by definition have a total measure of 180°.
This means that m<LMP and m<NMP are 180° together.
Therefore m<LMP + m<NMP = 180°.
[substitution property]
(-16x + 13)° + (-20x + 23)° = 180°
[associative property of addition]
(-36x + 36)° = 180°
-36x + 36 = 180
–36 –36
-36x = 144
÷-36 ÷-36
x = -4
_________________
Since m<LMP = (-16x + 13)°.
Using substitution with x = -4:
m<LMP = (-16(-4) + 13)° = (64 + 13)° = 77°.
Since m<NMP = (-20x + 23)°.
Using substitution with x = -4:
m<NMP = (-20(-4) + 23)° = (80 + 23)° = 103°.
This is true because 77° + 103° = 180°.