Question

Tìm x e Z:

2x+1 là bội của x-3

Giups mik gấp vs ạ. plsss

Answer 1

\(2x+1=2x-6+7=2\left(x-3\right)+7\)

\(=>x-3\inƯ\left(7\right)\)

\(Ư\left(7\right)=\left\{1;-1;7;-7\right\}\)

\(=>\left\{{}\begin{matrix}x-3=1\\x-3=-1\\x-3=7\\x-3=-7\end{matrix}\right.=>\left\{{}\begin{matrix}x=4\\x=2\\x=10\\x=-4\end{matrix}\right.\)

Answer 2

\(\Leftrightarrow2x-6+7⋮x-3\)

=>\(x-3\in\left\{1;-1;7;-7\right\}\)

hay \(x\in\left\{4;2;10;-4\right\}\)