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=
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/01 11:45:26
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=
3(X+Y)²-(X-Y)+2(X+Y)²+(X-Y)-5(X+Y)²
=3(X+Y)²+2(X+Y)²-5(X+Y)²-(X-Y)+(X-Y)
=0
全都抵消了,等于零