⑴√[(4a²－8a＋4)／(a²b³)]
=√[4(a²－2a＋1)／(a²b³)]
=2√[(a-1)²/(a²b³)]
=2(a-1)·(√b)/(ab²)
.
⑵√[a³／(a³＋2a²b＋ab²)]
=√[a²／(a²＋2ab＋b²)]
=a·√[1/(a+b)²]
=a/(a+b)