[질문] 또!

(a－b)(a2＋ab＋b2)=a3－b3, (a＋b＋c)2=a2＋b2＋c2＋2ab＋2bc＋2ca, (a＋b)3=a3＋3a2b＋3ab2＋b3, (a－b)3=a3-3a2b＋3ab2-b3, (a2＋ab＋b2)(a2－ab＋b2)=