X^3+Y^3+Z^3=(X+Y)(X^2-XY+Y^2)+Z^3
=-Z((X+Y)^2-3XY)+Z^3
=-Z^3+3XYZ+Z^3
=3XYZ
LZ题目错了吧~Z^3?哦，( ⊙ o ⊙ )是的，问题补充已改恩，如上~望采纳0 0