已知(x+y)(x+y+2)-8=0,则x+y的值是?过程中从【(x+y)^2+2(x+y)-8=0】→【(x+y+4)(x+y-2)=0】这部不理解,希望亲告诉我如何化简得到的!
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/24 04:27:33
![已知(x+y)(x+y+2)-8=0,则x+y的值是?过程中从【(x+y)^2+2(x+y)-8=0】→【(x+y+4)(x+y-2)=0】这部不理解,希望亲告诉我如何化简得到的!](/uploads/image/z/7084366-70-6.jpg?t=%E5%B7%B2%E7%9F%A5%28x%2By%29%28x%2By%2B2%29-8%3D0%2C%E5%88%99x%2By%E7%9A%84%E5%80%BC%E6%98%AF%3F%E8%BF%87%E7%A8%8B%E4%B8%AD%E4%BB%8E%E3%80%90%28x%2By%29%5E2%2B2%28x%2By%29-8%3D0%E3%80%91%E2%86%92%E3%80%90%28x%2By%2B4%29%28x%2By-2%29%3D0%E3%80%91%E8%BF%99%E9%83%A8%E4%B8%8D%E7%90%86%E8%A7%A3%2C%E5%B8%8C%E6%9C%9B%E4%BA%B2%E5%91%8A%E8%AF%89%E6%88%91%E5%A6%82%E4%BD%95%E5%8C%96%E7%AE%80%E5%BE%97%E5%88%B0%E7%9A%84%21)
已知(x+y)(x+y+2)-8=0,则x+y的值是?过程中从【(x+y)^2+2(x+y)-8=0】→【(x+y+4)(x+y-2)=0】这部不理解,希望亲告诉我如何化简得到的!
已知(x+y)(x+y+2)-8=0,则x+y的值是?
过程中从【(x+y)^2+2(x+y)-8=0】→【(x+y+4)(x+y-2)=0】这部不理解,希望亲告诉我如何化简得到的!
已知(x+y)(x+y+2)-8=0,则x+y的值是?过程中从【(x+y)^2+2(x+y)-8=0】→【(x+y+4)(x+y-2)=0】这部不理解,希望亲告诉我如何化简得到的!
我教个更简单的方法
令x+y=t
所以原式=t(t+2)-8=0
t²+2t-8=0
(t-2)(t+4)=0
t=2或t=-4
所以x+y的值是2或-4