I'm trying to do an intergration using the t-substitution so I've been reading examples and I keep loosing track on a similar fraction problem. I don't understand how

$\displaystyle \frac{4}{3+(10t/(1+t^2))} * \frac{2}{1+t^2} = \frac{8}{3t^2+10t+3}$

Any insight on how you can manipulate this is greatly appreciated

Cheers,

Isk