\(xy=-\left(x+y\right)\)
\(\Leftrightarrow xy+x+y=0\)
\(\Leftrightarrow x.\left(y+1\right)+\left(y+1\right)=1\)
\(\Leftrightarrow\left(x+1\right).\left(y+1\right)=1\)
.....
Đúng 0
Bình luận (0)