Question

Giá trị nhỏ nhất của |2y + 7,4| +6,2+|-x+3,1|

Answer 1

De \(\left|2y+7,4\right|+6,2+\left|-x+3,1\right|\) dat GTNN thi

\(\left|2y+7,4\right|\) va \(\left|-x+3,1\right|\) dat GTNN

Ma \(\begin{cases}\left|2y+7,4\right|\ge0\\\left|-x+3,1\right|\ge0\end{cases}\)

=> \(\left|2y+7,4\right|+\left|-x+3,1\right|\ge0\) do phai dat GTNN

=>\(\left|2y+7,4\right|+\left|-x+3,1\right|=0\)

=> GTNN cua \(\left|2y+7,4\right|+6,2+\left|-x+3,1\right|\)=0+6,2=6,2