Question

Tìm x,y thỏa mãn :

| x²+2x|+|y² —9|=0

Answer 1

Do \(\left\{{}\begin{matrix}\left|x^2+2x\right|\ge0\\\left|y^2-9\right|\ge0\end{matrix}\right.\)

Nên \(\left|x^2+2x\right|+\left|y^2-9\right|\ge0\)

Dấu "=" xảy ra khi:

\(\left\{{}\begin{matrix}x^2+2x=0\\y^2-9=0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}x=0\\x=-2\end{matrix}\right.\\\left[{}\begin{matrix}y=3\\y=-3\end{matrix}\right.\end{matrix}\right.\)