Answer:
Step-by-step explanation:
7.
72+89+99+2x+3x=(5-2)*180
260+5x=3*180
5x=540-260
5x=280
x=56°
8.
56+94+1.5x+x+4.5x=360
7x=360-150=210
x=30°
9.
x+9+x+120+156+145+90=(6-2)×180
2x=720-520
2x=200
x=100
10.
60+x+x+x+x=(5-2)×180
4x=540-60
4x=480
x=120°
11.
60+64+36+48+x+x=360
2x=360-208
2x=152
x=76°
12.
72+24+58+2x-6+86+x=(6-2)×180
3x=720-234=486
x=162°
