>>339
3/16の４乗根+1/27の４乗根=5/6･3の４乗根
(3/16)^(1/4)=(1/2)*(3^(1/4))
(1/27)^(1/4)=(3/81)^(1/4)=(1/3)*(3^(1/4))
これで３の４乗根で（同類項を）くくる。