A.4yz
B.8xy
C.4xy-4yz
D.8xz
A.4yz
B.8xy
C.4xy-4yz
D.8xz
解:
(x+y+z)²-(-x+y+z)²+(x-y+z)²-(x+y-z)²
=[(x+y+z)²-(-x+y+z)²]+[(x-y+z)²-(x+y-z)²]
=(x+y+z-x+y+z)(x+y+z+x-y-z)+(x-y+z+x+y-z)(x-y+z-x-y+z)
=(2y+2z)×2x+2x×(2z-2y)
=2x[(2y+2z)+(2z-2y)]
=2x×4z
=8xz
选D!!!!!!!!!!!!
开始用的是平方差公式!!!