Answer:
7.
∠M=51°
8.∠ABC=125°
Step-by-step explanation:
when we extend one line of a triangle ,the external angle is equal to the sum of two opposite internal angles.
151-2y=84+6y+3
151-2y=87+6y
151-87=6y+2y
64=8y
y=64/8=8
∠M=6y+3=6×8+3=48+3=51°
8.
20x-15=90+5x
20x-5x=90+15
15x=105
x=105/15=7
∠ABC=20x-15=20×7-15=140-15=125°
