X=100,Y=53,Z=70.100×0.17+53=70 请问：现已知Z 求X=?Y=?怎么算

(x+y-z)(x-y+z)= 14x+4y+z=200,x+y+z=100求解x,y,z X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 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)=? x+y+z=12 x-y+z=2 x-z+y+a=90 x+y+a+z=100,求x y z a (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 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 fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 z+=x>y?++x: x=y; y=z; z=x/y 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=30 120x=600z 100y=400z (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) 100x+10y+z=27(x+y+z) x+z=y+1 100z+10y+x-100x-10y-z=99 解方程组100x+10y+z=27(x+y+z) x+z=y+1 100z+10y+x-100x-10y-z=99 .急. z=x^(y/z) 偏导数 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 若z分之x+y+z=y分之x-y+z=x分之-x+y+z,求xyz分之(x+y)(y+z)(z+x)