Question

C= |x-2,5 |+ |y+1 |+4/5

Answer 1

Đề bài là tìm Min à ?

Với mọi x, y ta có :

\(\left\{{}\begin{matrix}\left|x-2,5\right|\ge0\\\left|y+1\right|\ge0\end{matrix}\right.\)

\(\Leftrightarrow\left|x-2,5\right|+\left|y+1\right|\ge0\)

\(\Leftrightarrow\left|x-2,5\right|+\left|y+1\right|+\frac{4}{5}\ge\frac{4}{5}\)

\(\Leftrightarrow C\ge\frac{4}{5}\)

Dấu "=" xảy ra \(\Leftrightarrow\left\{{}\begin{matrix}\left|x-2,5\right|=0\\\left|y+1\right|=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=2,5\\y=-1\end{matrix}\right.\)

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