Question

Tìm x biết (2×+5):(x+1)

các bạn ơi giúp mình với. Nhanh lên nhé . Mình cần nửa tiếng nữa thôi .

Answer 1

\(2x+5⋮x+1\)

Mà \(x+1⋮x+1\)

\(\Leftrightarrow\left\{{}\begin{matrix}2x+5⋮x+1\\2x+2⋮x+1\end{matrix}\right.\)

\(\Leftrightarrow3⋮x+1\)

\(\Leftrightarrow x+1\inƯ\left(3\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}x+1=1\\x+1=3\\x+1=-1\\x+1=-3\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\\x=-4\end{matrix}\right.\)

Vậy ..

Answer 2

\(\dfrac{2x+5}{x+1}=\dfrac{2x+2+3}{x+1}=\dfrac{2\left(x+1\right)+3}{x+1}=\dfrac{2\left(x+1\right)}{x+1}+\dfrac{3}{x+1}=2+\dfrac{3}{x+1}\)

=> x+1 thuộc Ư(3)={-1,-3,1,3}

=> x={-2,-4,0,2}