Question

[Lương]

|x+2|+y²=0 tìm x và y

Answer 1

[Nguyễn Ngọc Anh Minh]

\(\left|x+2\right|+y^2=0\) (1)

Do

\(\left|x+2\right|\ge0;y^2\ge0\)

\(\left(1\right)\Leftrightarrow\left\{{}\begin{matrix}\left|x+2\right|=0\\y^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-2\\y=0\end{matrix}\right.\)

Answer 2

[Nguyễn Lê Phước Thịnh]

Ta có: \(\left|x+2\right|>=0\forall x\)

\(y^2>=0\forall y\)

Do đó: \(\left|x+2\right|+y^2>=0\forall x,y\)

Dấu '=' xảy ra khi \(\left\{{}\begin{matrix}x+2=0\\y=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x=-2\\y=0\end{matrix}\right.\)