Câu hỏi của Tran Manh Hung

Question

Tim x biet

(x+7) chia hết cho (x+2)

Nguyễn Nam · Accepted Answer

Ta có: $x+7⋮x+2$

$\Rightarrow\left(x+2\right)+5⋮x+2$

$\Rightarrow5⋮x+2$

$\Rightarrow x+2U\left(5\right)=\left\{-1;1;-5;5\right\}$

$\Rightarrow\left\{{}\begin{matrix}x+2=-1\Rightarrow x=-3\x+2=1\Rightarrow x=-1\x+2=-5\Rightarrow x=-7\x+2=5\Rightarrow x=3\end{matrix}\right.$

Vậy $x\in\left\{-3;-1;-7;3\right\}$Câu trả lời: Ta có: $x+7⋮x+2$

$\Rightarrow\left(x+2\right)+5⋮x+2$

$\Rightarrow5⋮x+2$

$\Rightarrow x+2U\left(5\right)=\left\{-1;1;-5;5\right\}$

$\Rightarrow\left\{{}\begin{matrix}x+2=-1\Rightarrow x=-3\x+2=1\Rightarrow x=-1\x+2=-5\Rightarrow x=-7\x+2=5\Rightarrow x=3\end{matrix}\right.$

Vậy $x\in\left\{-3;-1;-7;3\right\}$

Chương II : Số nguyên