`a) x + 12 : 4 = 3`
`x + 3 = 3`
`x = 3 - 3`
`x= 0`
Vậy `x = 0`
``
`b) x - 24 . 2 - 10 = 425`
`x - 48 - 10 = 425`
`x - 48 = 425 + 10`
`x - 48 = 435`
`x = 435 + 48`
`x = 483`
Vậy `x = 483`
``
`c) 3x + 5x + x = 540`
`( 3 + 5 + 1) x = 540`
`9x = 540`
`x = 540 : 9`
`x = 60`
Vậy `x = 60`
``
`d) 67 - 17 . ( 7 - x) = 50`
`17 . ( 7 - x) = 67 - 50`
`17 . ( 7 - x ) = 17`
`( 7 - x ) = 17 : 17`
`7 - x = 1`
`x = 7 - 1`
`x = 6`
Vậy `x = 6`
``
`e) 12 + x : 2 = 15`
`x : 2 = 15 - 12`
`x : 2 = 3`
`x = 3 . 2`
`x = 6`
``
`f)` thiếu đề
`g) ( x + 12) : 4 = 3`
`x + 12 = 3 . 4`
`x + 12 = 12`
`x = 12 - 12`
`x = 0`
``
`h) ( x - 24) . 2 = 10`
`( x - 24) = 10 : 2`
`x - 24 = 5`
`x = 5 + 24`
`x = 29`
Vậy `x = 29`
``
`i) 12 + x : 2 = 17`
`x : 2 = 17 - 12`
`x : 2 = 5`
`x = 5 . 2`
`x = 10`
Vậy `x = 10`