tolong banget di jawab no.3 pakai cara

n+9=17 n=8
20-i=12 i=8

susah banget

n + 9 = 17
n = 17-9
n = 8

20 - i = 12
-i = 12-20
-i = -8
i = -8/-1
i = 8

hp = {8,8}