x+y+z=2 x-2y+z=-1 x+2y+3z=-1 解三元一次方程,

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-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) 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 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 x+y+z=6 x+2y+3z=14 y+1=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)=? 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 (x+y-z)^2-(x-y+z)^2=? (x-y-z)*( )=x^2-(y+z)^2 填空 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) matlab解对数方程组[x,y,z]=solve('0.29744*x/(3+0.1*x+y+z)=(log10((3+x+y+z)/(3+0.1*x+y+z)))^2','0.79*x/(3+0.1*y+z)=(log10((3+x+y+z)/(3+0.1*x+y+z)*(3+y+z)/(3+0.1*y+z)))^2','1.25*x/(3+0.1*z)=(log10((3+x+y+z)/(3+0.1*x+y+z)*(3+y+z)/(3+0.*1y+z)*(3+z)/ 分解因式:f(x,y,z)=x^2(y-z)+y^2(z-x)+z^2(x-y) 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y=