1) 15a - 60 = 42 + 8a - 32
15a - 8a = 60 + 42 - 32
7a = 70
a = 70 ÷ 7
a = 10
2) 18y + 18 = 36 + 12y + 12
18y - 12y = - 18 + 36 + 12
6y = 30
y = 30 ÷ 6
y = 5
3) 7k + 35 - 54 = 4k + 20
7k - 4k = - 35 + 54 + 20
3k = 39
k = 39 ÷3
k = 13
4) 17c - 34 - 36 = 19 + 12c - 24
17c - 12c = 34 + 36 + 19 - 24
5c = 65
c = 65 ÷ 5
c = 13