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a/ \(A=x-2009-4\sqrt{x-2009}+4=\left(\sqrt{x-2009}-2\right)^2\ge0\)
\(A_{min}=0\) khi \(\sqrt{x-2009}-2=0\Rightarrow x=2013\)
b/ \(\frac{1}{4}-\frac{\sqrt{x-2009}-1}{x-2009}+\frac{1}{4}-\frac{\sqrt{y-2010}-1}{y-2010}+\frac{1}{4}-\frac{\sqrt{z-2011}-1}{z-2011}=0\)
\(\Leftrightarrow\frac{x-2009-4\sqrt{x-2009}+4}{4\left(x-2009\right)}+\frac{y-2010-4\sqrt{y-2010}+4}{4\left(y-2010\right)}+\frac{z-2011-4\sqrt{z-2011}+4}{4\left(z-2011\right)}=0\)
\(\Leftrightarrow\frac{\left(\sqrt{x-2009}-2\right)^2}{4\left(x-2009\right)}+\frac{\left(\sqrt{y-2010}-2\right)^2}{4\left(y-2010\right)}+\frac{\left(\sqrt{z-2011}-2\right)^2}{4\left(z-2011\right)}=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\sqrt{x-2009}-2=0\\\sqrt{y-2010}-2=0\\\sqrt{z-2011}-2=0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x=2013\\y=2014\\z=2015\end{matrix}\right.\)
\(\frac{x+1}{2012}+\frac{x+2}{2011}=\frac{x+3}{2010}+\frac{x+4}{2009}\)
\(\Leftrightarrow\frac{x+1}{2012}+1+\frac{x+2}{2011}+1=\frac{x+3}{2010}+1+\frac{x+4}{2009}+1\)
\(\Leftrightarrow\frac{x+2013}{2012}+\frac{x+2013}{2011}=\frac{x+2013}{2010}+\frac{x+2013}{2009}\)
\(\Leftrightarrow\left(x+2013\right)\left(\frac{1}{2012}+\frac{1}{2011}-\frac{1}{2010}-\frac{1}{2009}\right)=0\Leftrightarrow x=-2013\)
\(\frac{x+1}{2012}+\frac{X+2}{2011}=\frac{X+3}{2010}+\frac{X+4}{2009}.\)
\(\Leftrightarrow\frac{X+1}{2012}+\frac{X+2}{2011}+2=\frac{X+3}{2010}+\frac{X+4}{2009}+2\)
\(\Leftrightarrow\frac{x+1}{2012}+1+\frac{x+2}{2011}+1=\frac{x+3}{2010}+1+\frac{x+4}{2009}+1\)
\(\Leftrightarrow\frac{x+2013}{2012}+\frac{x+2013}{2012}=\frac{x+2013}{2010}+\frac{x+2013}{2009}\)
\(\Leftrightarrow\left(x+2013\right).\left\{\frac{1}{2012}+\frac{1}{2011}-\frac{1}{2010}-\frac{1}{2009}\right\}=0\)
Mà \(\frac{1}{2012}+\frac{1}{2011}-\frac{1}{2010}-\frac{1}{2009}>0\)
\(\Leftrightarrow x+2013=0\)
\(\Leftrightarrow x=-2013\)
KL ; PT có Nghiệm \(S=\left\{-2013\right\}\)
\(\frac{3-x}{2009}-\frac{2-x}{2010}+\frac{1-x}{2011}=-1\)
\(\frac{3-x}{2009}+1-\left(\frac{2-x}{2010}+1\right)+\frac{1-x}{2011}+1=0\)
\(\frac{2012-x}{2009}-\frac{2012-x}{2010}+\frac{2012-x}{2011}=0\)
\(\left(2012-x\right)\left(\frac{1}{2009}-\frac{1}{2010}+\frac{1}{2011}\right)=0\)
Vì \(\frac{1}{2009}-\frac{1}{2010}+\frac{1}{2011}\ne0\)
\(\Rightarrow2012-x=0\)
\(\Rightarrow x=2012\)
pt <=> (2-x/2009 + 1) = (1-x/2010 + 1) + (1 - x/2011)
<=> 2011-x/2009 = 2011-x/2010 + 2011-x/2011
<=> 2011-x/2009 - 2011-x/2010 - 2011-x/2011 = 0
<=> (2011-x).(1/2009-1/2010-1/2011) = 0
<=> 2011-x=0 ( vì 1/2009-1/2010-1/2011 khác 0 )
<=> x=2011
Vậy x=2011
Tk mk nha
lấy cả 2 vế trừ đi 3
\(\frac{x-2010-2011}{2009}+\frac{x-2009-2011}{2010}+\frac{x-2009-2010}{2011}=3\)
\(\Leftrightarrow\left(\frac{x-2010-2011}{2009}-1\right)+\left(\frac{x-2009-2011}{2010}-1\right)+\left(\frac{x-2009-2010}{2011}-1\right)=0\)
\(\Leftrightarrow\frac{x-6030}{2009}+\frac{x-6030}{2010}+\frac{x-6030}{2011}=0\)
\(\Leftrightarrow\left(x-6030\right)\left(\frac{1}{2009}+\frac{1}{2010}+\frac{1}{2011}\right)\)
\(\Leftrightarrow x-6030=0\)(vì \(\frac{1}{2009}+\frac{1}{2010}+\frac{1}{2011}>0\))
\(\Leftrightarrow x=6030\)
Vậy ................