Answer:
x=15
angle b=7*15=105
angle a=180-105=75
angle c=2x=30
Step-by-step explanation:
b=7x
sum of straight angle :=180
isoceles traingle = 2 sides are equal, and two angles are equal
b+a=180
7x+a=180
sum of traingle =180
2a+c=180
2a+2x=180 first equation
7x+a=180 second equation
solve by elimination ( multiply second equation by 2)
2a+2x=180
2a+14x=360 ( subtract)
2a+2x-2a-14x=180-360
-12x=-180
x=-180/12=
x=15
angle b=7*15=105
angle a=180-105=75
angle c=2x=30
