已知:(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)]/xyz的值已知:(x+y-z)/z=(x-y+z)/y=(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)]/xyz的值 题目中写错个等号,汗...

问题描述:

已知:(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)]/xyz的值
已知:(x+y-z)/z=(x-y+z)/y=(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)]/xyz的值
题目中写错个等号,汗...

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

[(x+y)(y+z)(x+z)]/xyz
={[(x+y-z)+z][(y+z-x)+x][(x+z-y)+y]}/xyz
={[(x+y-z)+z]/z}{[(y+z-x)+x]/x}{[(x+z-y)+y]/y}
令(x+y-z)/z=(x-y+z)/y=(y+z-x)/x=K
则[(x+y)(y+z)(x+z)]/xyz=(K+1)^3
不知道你这个K有没有值的!

设x+y-z/z=x-y+z/y=y+z-x/x=k有x+y-z=kzx-y+z=kyy+z-x=kx三式相加得x+y+z=k(x+y+z) k=1 得x+y=(k+1)zx+z=(k+1)yy+z=(k+1)x当x+y+z≠0时(x+y)(y+z)(x+z)/xyz=(k+1)^3xyz/xyz=(k+1)^3=8当x+y+z=0时x+y=-z,x+...