来自孙福明的问题
已知x=1175,y=2522,则(x+y)2-(x-y)2的值等于()A.16B.13C.23D.58
已知x=1175,y=2522,则(x+y)2-(x-y)2的值等于()
A.16
B.13
C.23
D.58
1回答
2020-01-31 23:53
已知x=1175,y=2522,则(x+y)2-(x-y)2的值等于()A.16B.13C.23D.58
已知x=1175,y=2522,则(x+y)2-(x-y)2的值等于()
A.16
B.13
C.23
D.58
(x+y)2-(x-y)2,
=(x+y+x-y)(x+y-x+y),
=2x•2y,
=4xy,
当x=1175