(x+y-z)²+(x+y-z)(x+y+z)-2z(x-y)
=[(x+y)-z]²+[(x+y)-z][(x+y)+z]-2z(x-y)
=(x+y)²-2z(x+y)+z²+(x+y)²-z²-2z(x-y)
=-2z[(x+y)+(x-y)]
=-2z(2x)
=-4xz

应该是式子错了!没有答案!


很高兴为您解答,祝你学习进步!【the 1900】团队为您答题.
有不明白的可以追问!如果您认可我的回答.
请点击下面的【选为满意回答】按钮.
如果有其他问题请另发或点击向我求助,答题不易,请谅解,谢对不起我打错了呢。。原式是若x+y=6,xy=-8,求代数式(x-y+z)^2+(x+y-z)(x+y+z)-2·z(x-y)(x-y+z)²+(x+y-z)(x+y+z)-2z(x-y)=[(x-y)-z]²+[(x+y)-z][(x+y)+z]-2z(x-y)=(x-y)²-2z(x-y)+z²+(x+y)²-z²-2z(x-y)=(x-y)²+(x+y)²=(x²-2xy+y²)+(x²+2xy+y²)=2x²+2y²=2(x²+y²)=2[(x+y)²-2xy]=2×[6²-2×(-8)]=2×(36+16)=2×52=104