Question

\(\dfrac{13}{5x+1}-1=\dfrac{8x}{x-3}\)

 

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Answer 1

đk x khác -1/5 ; 3 

\(\dfrac{13}{5x+1}-1=\dfrac{8x}{x-3}\Rightarrow13\left(x-3\right)-\left(5x+1\right)\left(x-3\right)=8x\)

\(\Leftrightarrow13x-39-\left(5x^2-14x-3\right)=8x\Leftrightarrow-5x^2+19x-36=0\)

\(\Leftrightarrow-5\left(x^2-\dfrac{19}{5}x\right)-36=0\Leftrightarrow5\left(x^2-\dfrac{19}{5}\right)+36=0\)

\(\Leftrightarrow5\left(x^2-\dfrac{2.19}{10}x+\dfrac{19^2}{100}-\dfrac{19^2}{100}\right)+36=0\Leftrightarrow5\left(x-\dfrac{19}{10}\right)^2+\dfrac{1081}{20}=0\)( vô lí ) 

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