cứu mình với ( ko lm tắt nha )

Giải thích các bước giải:

 `a) 15 : ( x + 2 ) = 3`

`x + 2 = 15 : 3`

`x + 2 = 5`

`x = 5 - 2`

`x = 3`

Vậy `x = 3`

`-----`

`c) 240 : ( x - 5 ) = 2^2 . 5^2 - 20`

`240 : ( x - 5 ) = 4 . 25 - 20`

`240 : ( x - 5 ) = 100 - 20`

`240 : ( x - 5 ) = 80`

`x - 5 = 240 : 80`

`x - 5 = 3`

`x = 3 + 5`

`x = 8`

Vậy `x=8`

`------`

`e) 5( x + 35 ) = 515`

`x + 35 = 515 : 5`

`x + 35 = 103`

`x = 103 - 35`

`x = 68`

Vậy `x= 68`

`-----`

`g) 541 - ( 218 + x ) = 73`

`218 + x = 541 - 73`

`218 + x = 468`

`x = 468 - 218`

`x = 250`

Vậy `x=250`

`-----`

`b) 20 : ( x + 1 ) = 2`

`x + 1 = 20 : 2`

`x + 1 = 10`

`x = 10 - 1`

`x = 9`

Vậy `x=9`

`-----`

`d) 96 - 3 ( x + 1 ) = 42`

`3( x + 1 ) = 96 - 42`

`3 ( x + 1 ) = 54`

`x + 1 = 54 : 3`

`x + 1 = 18`

`x = 18 - 1`

`x = 17`

Vậy `x=17`

`-----`

`f) 12x - 33 = 3^2 . 3^3`

`12x - 33 = 9 . 27`

`12x - 33 = 243`

`12x = 243 + 33`

`12x = 276`

`x = 276 : 12`

`x = 23`

Vậy `x=23`

`-----`

`h) 1230 : 3(x - 20 ) = 10`

`410( x - 20 ) = 10`

`x - 20 = 10 : 410`

`x - 20 = 10/410 = 1/41`

`x = 1/41 + 20`

`x = 1/41 + 820/41`

`x = 821/41`

Vậy `x=821/41`

`#By.`