Ta có :
\(\left(2x+1\right)y=7\)
Vì \(x,y\in N\Leftrightarrow2x+1\in N;2x+1,y\inƯ\left(7\right)\)
\(\Leftrightarrow\left\{{}\begin{matrix}2x+1=1\Leftrightarrow x=0\\y=7\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}2x+1=7\Leftrightarrow x=3\\y=1\end{matrix}\right.\)
Vậy ...
(2x+1).y=7
2x+1 = 7:y
2x+1 =2,575....
2x =2,575...+1
2x =3,575...
=3,575... : 2
=1,787...