a) 34 -2 ( 3-x ) = 30
2 ( 3-x ) = 34 -30
2 ( 3 -x ) = 4
3 - x = 4 : 2
3 - x = 2
x = 3 - 2
x = 1
b ) 315 - 7 ( x + 1 ) = 105
7 ( x + 1 ) = 315 - 105
7 ( x + 1 ) = 210
x + 1 = 210 : 7
x +1 = 30
x = 30 - 1
x = 29
c ) 233 - 7 ( x + 1 ) = 100
7 ( x + 1 ) = 233 - 100
7 ( x + 1 ) = 133
x + 1 = 133 : 7
x + 1 = 19
x = 19 - 1
x = 18