Question

帮忙解答一道数学题、、急！！！！谢啦~

（x+y+z)的平方减（x-y-z)的平方
需要过程

Answer 1

(x+y+z)^2-(x-y-z)^2=[(x+y+z)+(x-y-z)]*[(x+y+z)-(x-y-z)]=2x*2(y+z)
=4xy+4xz
用的是平方差公式

Answer 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]
=[2(y+z)][2x]
=4x(y+z)

Answer 3

设y+z=A 原题为 x+A 的平方 减 x-A 的 平方
等于4xA 所以答案等于 4xy+4xz

Answer 4

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

Answer 5

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