Can someone please tell me why I have a +5 and +3 in the third step?

$\displaystyle \int[5x^2-6x-5 + \frac{10x+3}{x^2+1}]dx$

$\displaystyle

5 *\frac{1}{3}x^3-6*\frac{1}{2}x^2-5x+\int\frac{10x+3}{x^2+1}dx

$

$\displaystyle

\frac{5}{3}x^3-3x^2-5x+5\int\frac{10x}{x^2+1}+3\int\frac{3}{x^2+1}dx$