tolong jawab no 18 pake cara,makasih

110°+2b°=180°
2b°=180°-110°
2b°=70°
b=35°
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Maaf klo salah ):

= 110^o + 2b^o = 180^o
= 2b^o = 180^o - 110^o
= 2b^o = 70^o
= C.35^o
Maaf kalau salah 
Semoga membantu