x2-4y2+12yz-9z2

x2-4y2+12yz-9z2 x2+4y2+9z2-4xy-6xz+12yz,因式分解 因式分解x2+4y2+4xy-6xz-12yz+5z2 x2-y2-z2+2yz 因式分解 x2-y2-z2-2yz因式分解,求 已知：x/2=y/3=z/4,求（x2+y2-z2-2xy）/（x2-y2+z2-2xz）除以（x2-y2-z2+2yz)/(x2+y2-z2+2xy) 已知：x/2=y/3=z/4,求（x2+y2-z2-2xy）/（x2-y2+z2-2xz）除以（x2-y2-z2+2yz)/(x2+y2-z2+2xy) ：x3+y3-z3=96 xyz=4 x2+y2+z2-xy+yz+xz=12 求x+y-z xy=m,且1/x2+1/y2=n,则（x-y)2=3y=x+2z,那么x2+9y2+4z2-6xy-12yz+4xz= 已知,x/2=y/3=z/4,求xy+yz+zx/x2+y2+z2????? 因式分解：3x2-11xy+6y2-xz-4yz-2z2 证X2+y2+z2≥xy+yz+xz x2+y2+z2-2xy+2yz+2zx=? x,y,z为正实数 求证 x2/(y2+z2+yz)+y2/(z2+x2+zx)+z2/(x2+y2+xy)>=1 已知：x3+y3-z3=96 xyz=4 x2+y2+z2-xy+yz+xz=12 求x+y-z 已知；x/3=y/4=z/6 求；（xy+yz+xz）/(X2+y2+z2) 已知2/x=3/y=4/z,求x2+y2+z2/xy+yz+zx的值. 已知：x/2=y/3=z/4,求xy+2yz-3xz/x2+y2+z2的值