Question

2(x+y)^2-(x+2y)^2 怎么计算？

2(x+y)^2-(x+2y)^2 怎么计算？

Answer 1

根据题意的：
因为2(x+y)^2-(x+2y)^2
=2x^2+4xy+2y^2-x^2-4xy-4y^2
=x^2-2y^2
所以原式=（x+√2y）（x-√2y）
答案满意的话，请给与采纳，谢谢

Answer 2

2(x+y)^2-(x+2y)^2=2(x^2+2xy+y^2)-(x^2+4xy+4y^2)
=2x^2+4xy+2y^2-x^2-4xy-4y^2
=x^2-2y^2

Answer 3

2(x+y)^2-(x+2y)^2
=2x^2+4xy+2y^2-x^2-4xy-4y^2
=x^2-2y^2
=（x+√2y）（x-√2y）

Answer 4

=2(x^2+2xy+y^2)-(x^2+4xy+4y^2)
=2x^2+4xy+2y^2-x^2-4xy-4y^2
=x^2-2y^2

追问

(2x+y)^2-(x+2y)^2 怎么计算？

追答

=4x^2+4xy+y^2-(x^2+4xy+4y^2)
=4x^2+4xy+y^2-x^2-4xy-4y^2
=3x^2-3y^2
=3(x^2-y^2)或=3(x+y)(x-y)