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11 tháng 12 2017

i think the health is very important for many people.Because it helps many people comfortable and fun.Beside you will protect your body from environment and change weather.It also helps you not tired , bored ....you should protect your healthy by : if you go out,you should wear warm clothers , don't wear shorts clothers in cold weather....finnally, health is very very important 

29 tháng 9 2022

???

10 tháng 12 2017

ĐKXĐ : \(4x^2+5x+1\ge0\Leftrightarrow\left(4x+1\right)\left(x+1\right)\ge0\Rightarrow\orbr{\begin{cases}x\le-1\\x\ge-\frac{1}{4}\end{cases}}\)

\(\sqrt{4x^2+5x+1}-2\sqrt{x^2-x+1}=9x-3\)

\(\Leftrightarrow\sqrt{4x^2+5x+1}-\frac{2\sqrt{7}}{3}-2\sqrt{x^2-x+1}+\frac{2\sqrt{7}}{3}-9x+3=0\)

\(\Leftrightarrow\frac{4x^2+5x+1-\frac{28}{9}}{\sqrt{4x^2+5x+1}+\frac{2\sqrt{7}}{3}}-2\left(\frac{x^2-x+1-\frac{7}{9}}{\sqrt{x^2-x+1}+\frac{\sqrt{7}}{3}}\right)+3\left(3x-1\right)=0\)

\(\Leftrightarrow\frac{4x^2+5x-\frac{19}{9}}{\sqrt{4x^2+5x+1}+\frac{2\sqrt{7}}{3}}-2.\frac{x^2-x+\frac{2}{9}}{\sqrt{x^2-x+1}+\frac{\sqrt{7}}{3}}+3\left(3x-1\right)=0\)

\(\Leftrightarrow\frac{\left(x-\frac{1}{3}\right)\left(4x+\frac{19}{3}\right)}{\sqrt{4x^2+5x+1}+\frac{2\sqrt{7}}{3}}-\frac{2\left(x-\frac{2}{3}\right)\left(x-\frac{1}{3}\right)}{\sqrt{x^2-x+1}+\frac{\sqrt{7}}{3}}+9\left(x-\frac{1}{3}\right)=0\)

\(\Leftrightarrow\left(x-\frac{1}{3}\right)\left(\frac{4x+\frac{19}{3}}{\frac{2\sqrt{7}}{3}}-\frac{2x-\frac{4}{3}}{\sqrt{x^2-x+1}+\frac{\sqrt{7}}{2}}+9\right)=0\)

\(\Rightarrow x=\frac{1}{3}\)(TMĐKXĐ)

10 tháng 12 2017

dùng liên hợp nhé bn