how does

$\displaystyle

\int \frac{-2x+1}{{x^2}+x+1}dx

$

become

$\displaystyle \int \frac{-2x-1}{{x^2}+x+1}dx\

+ 2 \int \frac{dx}{(x+{(1/2)^{2})}+(3/4)}

$

i got the completing the squares part but how does it turn to -1 and where did the 2 infront of the second integral come from...