通分；4x/5y²z与-3z/10x²y；x/x²+3x+2,-x/x²+2x+

1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 若3x-2y-z=0,x+4y-3z=0,求3x²+y²/4x²-y²+z
(x-3y+2z)²= 已知x²+y²-6x+2y+|z+3|+10=0,求x+z-y的值 已知实数x,y,z满足x²-6xy+10y²+4y+|z²-3z+2|+4=0,求(x+y x/2=y/3=z/5 x+3y-z/x-3y+z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 若x-y=6,xy=-8,求代数式(x+y+z)²+(x-y-z)(x-y+z)-2·z(x+y)的值 {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 已知4x-5y+2z=0,x+4y-3z=0,求(x²+y²+z²)/xy+yz+xz