把(X-Y)和(X+Y)各看作一个字母因式,合并同类项3(X+Y)²-(X-Y)+2(X+Y)²+(X-Y)-5(X-Y)²=

问题描述:

把(X-Y)和(X+Y)各看作一个字母因式,合并同类项3(X+Y)²-(X-Y)+2(X+Y)²+(X-Y)-5(X-Y)²=
2在后面是²,2在前面是与后面相乘.

5(X+Y)²-5(X-Y)²