$\frac{x}{x^2+3x+2} + \frac{x}{x^2-x+2} = \frac{1}{6}

crazyshou

\(\$\frac{x}{x^2+3x+2}+\frac{x}{x^2-x+2}=\frac{1}{6}\$分母除以\$x\$，化为\$\frac{1}{x+2/x+3}+\frac{1}{x+2/x-1}=\frac{1}{6}\$，令\$t=x+\frac{2}{x}\$。\)