Ta có:
\(\left(2x-1\right)^2+\left|2y-x\right|-8=12-5.2^2\)
=> \(\left(2x-1\right)^2+\left|2y-x\right|=12-20+8\)
=> \(\left(2x-1\right)^2+\left|2y-x\right|=0\)
nx:
\(\left(2x-1\right)^2\ge0với\forall x\)
\(\left|2y-x\right|\ge với\forall x,y\)
=> \(\left(2x-1\right)^2+\left|2y-x\right|\ge0với\forall x,y\)
Do đó:\(\left(2x-1\right)^2+\left|2y-x\right|=0\)
<=>\(\left\{\begin{matrix}2x-1=0\\2y-x=0\end{matrix}\right.\Leftrightarrow\left\{\begin{matrix}2x=1\\2y=2\end{matrix}\right.\)
<=>\(\left\{\begin{matrix}x=\frac{1}{2}\\2y=\frac{1}{2}\end{matrix}\right.\Leftrightarrow\left\{\begin{matrix}x=\frac{1}{2}\\y=\frac{1}{4}\end{matrix}\right.\)
Vậy x=1/2;y=1/4
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