{x+2y=3 3x+2z=11 y-3z=13 解方程{m÷2+n÷3=3 m÷3+4n÷18=2 解方程

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 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 x/2=y/3=z/5 x+3y-z/x-3y+z x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 若x+y+z=3y=2z,则x/x+y+z=? 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 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 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= 解下列方程组3x-y+z=3,2x+y-3z=11,x+y+z=123x-y+z=32x+y-3z=11x+y+z=12 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, x+y+z=6 x+2y+3z=14 y+1=z X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 3x-2y+2z=3,2x+y-3z=11,x+y+z=12