\(A=\left(x-9\right)^2+\left|2x-y-2\right|+10\)
Do \(\left(x-9\right)^2\ge0\forall x;\left|2x-y-2\right|\ge0\forall x;y\)
\(\Rightarrow A\ge0+0+10=10\forall x;y\)
Dấu "=" xảy ra \(\Leftrightarrow\left\{{}\begin{matrix}x-9=0\\2x-y-2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=9\\y=16\end{matrix}\right.\)