a.\(\left|2-3x\right|=-1\left(vô.lí\right)\)
Vậy pt vô nghiệm
b.\(\Leftrightarrow4x=5,8\)
\(\Leftrightarrow x=1,45\)
c.\(ĐK:x\ne1\)
\(\Rightarrow\dfrac{3}{x-1}+\dfrac{2}{x^2+x+1}=\dfrac{3x^2}{\left(x-1\right)\left(x^2+x+1\right)}\)
\(\Leftrightarrow\dfrac{3\left(x^2+x+1\right)+2\left(x-1\right)}{\left(x-1\right)\left(x^2+x+1\right)}=\dfrac{3x^2}{\left(x-1\right)\left(x^2+x+1\right)}\)
\(\Leftrightarrow3\left(x^2+x+1\right)+2\left(x-1\right)=3x^2\)
\(\Leftrightarrow3x^2+3x+3+2x-2-3x^2=0\)
\(\Leftrightarrow5x=-1\)
\(\Leftrightarrow x=-\dfrac{1}{5}\left(tm\right)\)
Vậy \(S=\left\{-\dfrac{1}{5}\right\}\)
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