Evaluate 40x+405x2+10x+4dx\displaystyle \int\frac{{{40}{x}+{40}}}{{{5}{x}^{{2}}+{10}{x}+{4}}}{\left.{d}{x}\right.} where 5x2+10x+4>0\displaystyle {5}{x}^{{2}}+{10}{x}+{4}>{0}.
First substitute u =  
Then 40x+405x2+10x+4dx=\displaystyle \int\frac{{{40}{x}+{40}}}{{{5}{x}^{{2}}+{10}{x}+{4}}}{\left.{d}{x}\right.}=\int   du
Now integrate with respect to u to get   + C
So 40x+405x2+10x+4dx\displaystyle \int\frac{{{40}{x}+{40}}}{{{5}{x}^{{2}}+{10}{x}+{4}}}{\left.{d}{x}\right.} =   + C