早教吧 育儿知识 作业答案 考试题库 百科 知识分享

(x+y+z)×(﹣x+y+z)×(x-y+z)×(x+y-z)=

题目详情
(x+y+z)×(﹣x+y+z)×(x-y+z)×(x+y-z)=
▼优质解答
答案和解析
原式={[(y+z)+x][(y+z)-x]}{[x-(y-z)][x+(y-z)]}
  =[(y+z)^2-x^2][x^2-(y-z)^2]
  =x^2(y+z)^2-x^4-[(y+z)(y-z)]^2+x^2(y-z)^2
  =x^2[(y+z)^2+(y-z)^2]-x^4-(y^2-z^2)^2
  =x^2(y^2+2yz+z^2+y^2-2yz+z^2)-x^4-(y^4-2y^2z^2+z^4)
  =x^2(2y^2+2z^2)-x^4-y^4+2y^2z^2-z^4
  =2x^2y^2+2y^2z^2+2x^2z^2-x^4-y^4-z^4