College Algebra 7th Edition

$\frac{2x+1}{x^{2}(x+1)}$
We form a common denominator: $\displaystyle \frac{1}{x^{2}}+\frac{1}{x^{2}+x}=\frac{1}{x^{2}}+\frac{1}{x(x+1)}=\frac{x+1}{x^{2}(x+1)}+\frac{x}{x^{2}(x+1)}=\frac{2x+1}{x^{2}(x+1)}$