Tolong jawab no 7 dan 8pakai cara makasih​

Jawaban:

7.

a.

2a+3a+4a = 180°

9a = 180°

a = 20°

b.

4c+56°+3c+89° = 180°

7c+145 = 180°

7c = 35°

c = 5°

8.

a.

6x+3x = 180°

9x = 180°

x = 20°

b.

65°+2y+3y = 270°

65°+5y = 270°

5y = 205°

y = 41°