You can
put this solution on YOUR website!i have looked on the web and not found much at all, however one pdf had an example where it multiplied by a "surd conjugate". Looking into this, it looks like

has the conjugate

. As for why...that is the definition of the conjugate. Simple as that.
As for the reason behind using a conjugate...it removes any irrational/surd parts, since

is

-->

.
Jon.