Answer:
∠MON = 99
Explanation:
∠LON = 180°
∠MON + ∠LOM = 180 -------equation
where:
∠MON = 8x - 13
∠LOM = 7x - 17
plugin values into the equation
8x - 13 + 7x - 17 = 180
8x + 7x - 13 - 17 = 180
15x - 30 = 180
15x = 180 + 30
x = 210 / 15
x = 14
plugin values to ∠MON = 8x - 13
∠MON = 8x - 13
∠MON = 8(14) - 13
∠MON = 99