giúp em bài này với ạ, em cảm ơn

`a) 250 : (10-x)=25`

`10-x=250 : 25`

`10-x=10`

`x=10-10`

`x=0`

Vậy `x=0`

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`b) 3x - 2018 : 2=23`

`3x-1009 = 23`

`3x=23+1009`

`3x=1032`

`x=1032 : 3`

`x=344`

Vậy `x=344`

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`c) (9x-21) : 3=2`

`9x - 21=3 xx 2`

`9x-21=6`

`9x=6+21`

`9x=27`

`x = 27:9`

`x=3`

Vậy `x=3`

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`d) 53(9-x)=53`

`9-x=53:53`

`9-x=1`

`x=9-1`

`x=8`

Vậy `x=8`

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`e) 231 + (312 -x)=531`

`312-x=531-231`

`312-x=300`

`x=312-300`

`x=12`

Vậy `x=12`

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`f) 15 : x+120 : 12=15`

`15 : x + 10 = 15`

`15 : x = 15-10`

`15 : x=5`

`x=15 : 5`

`x=3`

Vậy `x=3`