\(5\overrightarrow{IA}-7\overrightarrow{IB}-\overrightarrow{IC}=0\Leftrightarrow5\left(\overrightarrow{GA}-\overrightarrow{GI}\right)-7\left(\overrightarrow{GB}-\overrightarrow{GI}\right)-\left(\overrightarrow{GC}-\overrightarrow{GI}\right)=0\)

\(\Leftrightarrow3\overrightarrow{GI}=-5\overrightarrow{GA}+7\overrightarrow{GB}+\overrightarrow{GC}=-6\overrightarrow{GA}+6\overrightarrow{GB}\left(\overrightarrow{GA}+\overrightarrow{GB}+\overrightarrow{GC}=0\right)\)

\(\Leftrightarrow\overrightarrow{GI}=2\left(\overrightarrow{GB}-\overrightarrow{GA}\right)=2\overrightarrow{AB}\)\(\Leftrightarrow GI//AB\Rightarrow\frac{OA}{OI}=\frac{AB}{GI}=\frac{1}{2}\)

tìm max

\(\left(\frac{a}{\sqrt{bc}};\frac{b}{\sqrt{ca}};\frac{c}{\sqrt{ab}}\right)\rightarrow\left(x;y;z\right)\)\(\Rightarrow\)\(xyz=1\)\(\Rightarrow\)\(\hept{\begin{cases}x+y+z\ge3\\xy+yz+zx\ge3\end{cases}}\)

\(B=\Sigma\frac{1}{x+3}=\frac{-3\left(x+y+z\right)-5\left(xy+yz+zx\right)-3xyz+27}{4\left(x+3\right)\left(y+3\right)\left(z+3\right)}+\frac{3}{4}\le\frac{-9-15-3+27}{4\Pi\left(x+3\right)}+\frac{3}{4}=\frac{3}{4}\)

Dấu "=" xảy ra khi \(a=b=c\)

\(y=\frac{1}{x-1}\)

DKXĐ: x - 1 \(\ne\)0 

<=> x \(\ne\)1

=> TXĐ: \(ℝ\backslash\left\{1\right\}\)hoặc \(\left(-\infty;1\right)\)U\(\left(1;+\infty\right)\)hoặc \(\left(-\infty;+\infty\right)\backslash\left\{1\right\}\)

chụp và gửi

mà bạn tải qanda về rồi chụp rồi nó gửi câu trả lời cho

Số bị chia: x

Số chia là y

\(\Rightarrow\frac{x}{2y}=8\Rightarrow\frac{x}{y}=16\) => Thương của phép chia là 16

\(\frac{x}{3.16}=8\Rightarrow x=3.8.16=384\)