-(2x^20-7xy)-2[2x^2-(3x^2-5xy+y^2)]化简

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/15 11:28:43

-(2x^20-7xy)-2[2x^2-(3x^2-5xy+y^2)]化简
-(2x^20-7xy)-2[2x^2-(3x^2-5xy+y^2)]化简

-(2x^20-7xy)-2[2x^2-(3x^2-5xy+y^2)]化简
第一项错了吧,是平方
-(2x^2-7xy)-2[2x^2-(3x^2-5xy+y^2)]
=-2x^2+7xy-4x^2+2(3x^2-5xy+y^2)
=-6x^2+7xy+6x^2-10xy+2y^2
=-3xy-10xy+2y^2