Question

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

(x+y)^2+________ =(x-y)^2

Answer 1

(x+y)²=（x-y）²
x²+2xy+y²=x²-2xy+y²
2xy=-2xy
4xy=0
xy=0
被你给误导了 重新算一次
(x+y)²+________ =(x-y)²
空格中的式子就是(x-y)²-(x+y)²的差
(x-y)²-(x+y)²
=x²-2xy+y²-（x²+2xy+y²）
=x²-2xy+y²-x²-2xy-y²
=-4xy
即(x+y)² - 4xy =(x-y)²

Answer 2

(x+y)²=(x-y)²
x²+2xy+y²=x²-2xy+y²
4xy=0
∴x=0或y=0或x=y=0

Answer 3

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

Answer 4

=2x*2y =4xy (13)(x+y)^2-10(x+y)+25 =(x+y-5) (14)(x^2+2x)^2-(2x+4y^2)^2 =[(x +2x)+(2x+4y )][(x +2x)-(2x+4y

Answer 5

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

Answer 6

x^2+y^2=x^2+y^2