X+Y+Z=30 120X:100Y:200Z=3:2:1

X+Y+Z=30 120X:100Y:200Z=3:2:1 x+y+z=30 120x=600z 100y=400z x+y+z=30 x+y+z=30 120x=3*200z 100y=2*200z 这个方程怎么解三元一次方程 x+y+z=30 解方程：120x=3*200z 100y=2*200z x+y+z=12 x-y+z=2 x-z+y+a=90 x+y+a+z=100,求x y z a 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证? 解方程 Y=X+Z Y-Z=2 100Z+10Y+X-(100X+10Y+Z)=99 Y=X+ZY-Z=2100Z+10Y+X-(100X+10Y+Z)=99 6x+5y+3z=100 x+y+z=30 求 x y 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 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值 (x-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) + (y+z-2z)(x-2y+z)分之（x-z)(y-z)=?第三部分那个是 （y+z-2x)(x-2y+z)分之（x-z)(y-z) (x+y-z)(x-y+z)= 10X+Y+1/3Z=10Y+X 10X+Y+2/3Z=100X+Y (x+y-z)^2-(x-y+z)^2=? (x-y-z)*( )=x^2-(y+z)^2 填空 分解因式:f(x,y,z)=x^2(y-z)+y^2(z-x)+z^2(x-y)