no 1-3 bsk dikumpulkan pleaseeee

1.
2a + 3a = 90
5a = 90
a = 90/5
a = 18

46 + a + 29 + 5a + 15 = 180
6a + 90 = 180
6a = 180-90
6a = 90
a = 90/6
a = 15

2.