Bài 2. (2 điểm) Tìm số nguyên x, biết: a)$250:(x-5)-64-14$ b)$3(x+8)=17+(-23)$ c)$2(x-3) (-3) -1$

`a . ` `250:(x-5)=64-14`

`=>` `250:(x-5)=50`

`=>` `(x-5)=250:50`

`=>` `(x-5)=5`

`=>` `x-5=5`

`=>` `x=5+5`

`=>` `x=10`

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`b . ` `3(x+8)=17+(-23)`

`=>` `3(x+8)=-6`

`=>` `(x+8)=-2`

`=>` `x+8=-2`

`=>` `x=(-2)-8`

`=>` `x=-10`

Vậy `x=-10`

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`c . ` `2(x-3)^2=(-3)^2-1`

`=>` `2(x-3)^2=9-1`

`=>` `2(x-3)^2=8`

`=>` `(x-3)^2=4`

`=>` `(x-3)^2=2^2`

`=>` $\left[\begin{matrix} x-3=2\\ x-3=-2\end{matrix}\right.$

`=>` $\left[\begin{matrix} x=2+3\\ x=(-2)+3\end{matrix}\right.$

`=>` $\left[\begin{matrix} x=5\\ x=1\end{matrix}\right.$

Vậy `x \in { 5;1}`

`#me`