x+y+z=13 y-x=2 100x+z-x-100z=99 这个方程组怎么解

(x+y-z)(x-y+z)= 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? x+y+z=12 x-y+z=2 x-z+y+a=90 x+y+a+z=100,求x y z a 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 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^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) 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 X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) z+=x>y?++x: (x+y-z)^2-(x-y+z)^2=? (x-y-z)*( )=x^2-(y+z)^2 填空 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 解一道三元一次方程x+y+z=13,y-2=z,100z+10y+x+99=100x+10z+y. 10X+Y+1/3Z=10Y+X 10X+Y+2/3Z=100X+Y 分解因式:f(x,y,z)=x^2(y-z)+y^2(z-x)+z^2(x-y)