Tolong, y. Jawabannya

a. 65 + 90 + 2a + 3a = 360
155 + 5a = 360
5a = 360 - 155
5a = 205
a = 205 : 5
a = 41

b. 5b + b + 2b + 40 = 180
8b = 180 - 40
8b = 140
b = 140 : 8
b = 17,5