`(x-35)-120=0`
`x-35=120`
`x=120+35`
`x=155`
``
`23 xx(42-x)=23`
`42-x=23:23`
`42-x=1`
`x=42-1`
`x=41`
``
`(x+13):5=12
`x+13=12xx5`
`x+13=60`
`x=60-13`
`x=47`
``
`310-(118-x)=217`
`118-x=310-217`
`118-x=93`
`x=118-93`
`x=25`
( x - 35 ) - 120 = 0
(x-35)=120
x=120+35x=155.
23 x ( 42 - x ) = 23
42-x=23:23
42-x=1
x=42-1=41.
( x + 13 ) : 5 = 12
x+13=12x5
x+13=60
x=60-13=47.
310 - ( 118 - x ) = 217
118-x=310-217
118-x=93
x=118-93=25.