Bài 2B : Tìm số nguyên x a) 21+(2x-14)=23 b) 1-(12+3x)=7 c) -(2x+2)+25=-19 d) 26-(26-x)=0

`21+(2x-14)=23`

` 2x – 14 = 23 – 21`

`2x – 14 = 2`

`2x = 2 + 14`

`2x = 16`

`x = 16 : 2`

`x = 8`

vậy `x = 8`

`1-(12+3x)=7`

` 12 + 3x = 1 – 7 `

`12 + 3x = -6`

`3x = 12 – (-6)`

`3x = 18`

`x = 18 :3`

`x = 6`

vậy `x=6`

`-(2x+2)+25=-19`

`-(2x + 2 ) =  \-19 – 25`

`-2x + 2  = -44`

`-2x = – 44 – 2`

`-2x = -46`

`-x = – 46 : 2`

`-x = -23`

`x = -23`

Vậy `x = – 23`

`26-(26-x)=0`

`26 – x = 26 – 0`

`26 – x = 26`

`x = 26 – 26`

`x = 0`

Vậy `x = 0`

Xin hay nhất !!

 

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