Note that
sqrt (245) = sqrt ( 49 * 5) = 7sqrt (5) and
3sqrt (125) = 3 sqrt ( 25 * 5 ) = 15 sqrt (5)
So....the denominator is just 7sqrt (5) + 15sqrt (5) + 4sqrt (5) = 26sqrt (5)
So we have
6 3 sqrt (5) 3sqrt (5)
_________ = _________ _______ = ____________
26sqrt (5) 13sqrt (5) sqrt (5) 65