ĐKXĐ: \(x\ne0\)
\(\frac{\left(x+1\right)\left(x^2-x+1\right)-\left(x-1\right)\left(x^2+x+1\right)}{\left(x^2+x+1\right)\left(x^2-x+1\right)}-\frac{3}{x\left(x^4+x^2+1\right)}=0\)
\(\Leftrightarrow\frac{x^3+1-\left(x^3-1\right)}{x^4+x^2+1}-\frac{3}{x\left(x^4+x^2+1\right)}=0\)
\(\Leftrightarrow2-\frac{3}{x}=0\)
\(\Rightarrow x=\frac{3}{2}\)