1.3x^2*y-X^2*Y^2-3z^5-xy是几次多项式?是关于x的几次式?是关y的几次式?接字母x降幂排列.2.将（a-2b)看成一个字母,把代数式-（a-2b)^2-2-3(a-2b)^3+4(a-2b),接（a-2b)的降幂排列.3多项式：（a-4)x^3-x^b+x-b是关

试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 2(x+y)(x+y-z)+3(y-z)(x+y-z) 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) (x-3y+2z)(x+3y-2z) （x-2y+3z)(x+2y-3z) (2y-x-3z)(-x-2y-3z) 化简(x+Y)^2(y+z-x)(z+x-y)+(x-y)^2(x+y+z)(x+y-z) 计算题(x+y)^2(y+z-x)(z+x-y)+(x-y)^2(x+y+z)(x+y-z). 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) 化简(y-x)(z-x)/(x-2y+z)(x+y-2z)+（z-y)(x-y)/(x-2z+y)(y+z-2x)+(x-z)(y-z)/(y+z-2x)(x-2y+z) 计算:(y-x)(z-x)/(x-2y+z)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z)/(y+z-2x)(x-2y+z) 2(x+y-z)-3(x-y+z)-5(x+y-z)+6(x-y+z) 计算 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 化简-(-3x-y+2z)-{-x+【4x-(x-y-z)-3x+2z} 计算:x^2/(x-y)(x-z)+y^2/(y-x)(y-z)+z^2/(z-x)(z-y) (x+3y-2z)(x-3y-2z)-(x+3y-2z)^2 x+2y=3x+2z=4y+z 求x:y:z