a) 15 × `x` - 133 = 17
15 × `x` = 17 + 133
15 × `x` = 150
`x` = 150 : 15
`x` = 10
b) 165 + (30 - `x`) = 200
30 + `x` = 200 - 165
30 + `x` = 35
`x` = 35 - 30
`x` = 5
c) 5 × (`x` + 12) + 22 = 92
5 × (`x` + 12) = 92 - 22
5 × (`x` + 12) = 70
`x` + 12 = 70 : 5
`x` + 12 = 14
`x` = 14 - 12
`x` = 2