Question

1.tìm x,y \(\in z,biết:\)

a)xy+2x+y+11=0

b)\(\frac{1}{x}+\frac{1}{y}=\frac{1}{2}\)

giúp mk nhé

Answer 1

a) \(xy+2x+y+11=0\)

\(\Leftrightarrow x\left(y+2\right)+\left(y+2\right)+9=0\)

\(\Leftrightarrow\left(x+1\right)\left(y+2\right)=0-9\)

\(\Leftrightarrow\left(x+1\right)\left(y+2\right)=-9\)\(=-1.9=-3.3=-9.1\)

\(\Rightarrow\left[{}\begin{matrix}x+1=-1;y+2=9\\x+1=-3;y+2=3\\x+1=-9;y+2=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=-2;y=7\\x=-4;y=1\\x=-10;y=-1\end{matrix}\right.\)

Vậy:.............