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![](https://rs.olm.vn/images/avt/0.png?1311)
-4/1/3.1/3< x < -2/3.-11/12
-1/4/9< x < 11/18
-26/18< x < 11/18
Vậy x={-26/18;-25/18;.............;11/18}
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{x+2}{327}+\frac{x+3}{326}+\frac{x+4}{325}+\frac{x+5}{324}+\frac{x+349}{5}=0\)
\(\Leftrightarrow\)\(\frac{x+2}{327}+1+\frac{x+3}{326}+1+\frac{x+4}{325}+1+\frac{x+5}{324}+1 +\frac{x+349}{5}-4=0\)
\(\Leftrightarrow\)\(\frac{x+329}{327}+\frac{x+329}{326}+\frac{x+329}{325}+\frac{x+329}{324}+\frac{x+329}{5}=0\)
\(\Leftrightarrow\)\(\left(x+329\right)\left(\frac{1}{327}+\frac{1}{326}+\frac{1}{325}+\frac{1}{324}+\frac{1}{5}\right)=0\)
\(\Leftrightarrow\)\(x+329=0\) (vì 1/327 + 1/326 + 1/325 + 1/324 + 1/5 khác 0 )
\(\Leftrightarrow\)\(x=-329\)
Bài 1 :
\(\frac{x+2}{327}+\frac{x+3}{326}+\frac{x+4}{325}+\frac{x+5}{324}+\frac{x+349}{5}=0\)
\(\Leftrightarrow\)\(\left(\frac{x+2}{327}+1\right)+\left(\frac{x+3}{326}+1\right)+\left(\frac{x+4}{325}+1\right)+\left(\frac{x+5}{324}+1\right)+\left(\frac{x+349}{5}-4\right)=0\)
\(\Leftrightarrow\)\(\frac{x+329}{327}+\frac{x+329}{326}+\frac{x+329}{325}+\frac{x+329}{324}+\frac{x+329}{5}=0\)
\(\Leftrightarrow\)\(\left(x+329\right)\left(\frac{1}{327}+\frac{1}{326}+\frac{1}{325}+\frac{1}{324}+\frac{1}{5}\right)=0\)
Vì \(\left(\frac{1}{327}+\frac{1}{326}+\frac{1}{325}+\frac{1}{324}+\frac{1}{5}\right)\ne0\)
\(\Rightarrow\)\(x+329=0\)
\(\Rightarrow\)\(x=-329\)
Vậy \(x=-329\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(-4\frac{3}{5}\cdot2\frac{4}{23}\le x\le-2\frac{3}{15}:1\frac{6}{15}\)
=> \(-\frac{23}{5}\cdot\frac{50}{23}\le x\le\frac{-33}{15}:\frac{21}{15}\)
=> \(-10\le x\le\frac{-11}{7}\)
=> \(x\in\left\{-10;-9,-8,-7,-6,-5,-4,-3,-2,-1\right\}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
d) \(\frac{x+1}{2009}+\frac{x+2}{2008}+\frac{x+3}{2007}=\frac{x+10}{2000}+\frac{x+11}{1999}+\frac{x+12}{1998}\)
<=> \(\frac{x+1}{2009}+\frac{x+2}{2008}+\frac{x+3}{2007}-\frac{x+10}{2000}-\frac{x+11}{1999}-\frac{x+12}{1998}=0\)
<=> \(\left(\frac{x+1}{2009}+1\right)+\left(\frac{x+2}{2008}+1\right)+\left(\frac{x+3}{2007}+1\right)-\left(\frac{x+10}{2000}+1\right)-\left(\frac{x+11}{1999}+1\right)-\left(\frac{x+12}{1998}+1=0\right)\)
<=> \(\frac{x+2010}{2009}+\frac{x+2010}{2008}+\frac{x+2010}{2007}-\frac{x+2010}{2000}-\frac{x+2010}{1999}-\frac{x+2010}{1998}=0\)
<=>\(\left(x+2010\right).\left(\frac{1}{2009}+\frac{1}{2008}+\frac{1}{2007}-\frac{1}{2000}-\frac{1}{1999}-\frac{1}{1998}\right)=0\)
<=> x+2010 = 0 vì \(\frac{1}{2009}+\frac{1}{2008}+\frac{1}{2007}-\frac{1}{2000}-\frac{1}{1999}-\frac{1}{1998}\ne0\)
<=> x = -2010
x=2/3
Ta viết phương trình thành dạng \(\left|x-\frac{1}{3}\right|+\left|x-\frac{4}{3}\right|=\frac{9}{2}x\)
+) Xét khoảng \(x< \frac{1}{3}\)
\(pt\Leftrightarrow\left(\frac{1}{3}-x\right)+\left(\frac{4}{3}-x\right)=\frac{9}{2}x\)
\(\Leftrightarrow\frac{5}{3}-2x=\frac{9}{2}x\Leftrightarrow\frac{13}{2}x=\frac{5}{3}\Leftrightarrow x=\frac{10}{39}\left(tm\right)\)
+) Xét khoảng \(\frac{1}{3}\le x\le\frac{4}{3}\)
\(pt\Leftrightarrow\left(x-\frac{1}{3}\right)+\left(\frac{4}{3}-x\right)=\frac{9}{2}x\)
\(\Leftrightarrow1=\frac{9}{2}x\Leftrightarrow x=\frac{2}{9}\)(L)
Xét khoảng \(x>\frac{4}{3}\)
\(pt\Leftrightarrow\left(x-\frac{1}{3}\right)+\left(x-\frac{4}{3}\right)=\frac{9}{2}x\)
\(\Leftrightarrow2x-\frac{5}{3}=\frac{9}{2}x\Leftrightarrow\frac{5}{3}=\frac{-5}{2}x\)(loại vì x chắc chắn âm)
Vậy tập nghiệm \(S=\left\{\frac{10}{39}\right\}\)