x=3y-24 2x-3=0 x+y+z=140 这个三元一次方程组谁会啊?

证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 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-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 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 2x+z=10 x+y-z=4 3x-y-z=0 {2x+y=10 {x-y+z=4 {3x-y-z=0 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 x/2=y/3=z/5 x+3y-z/x-3y+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=? x+2y=3x+2z=4y+z 求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 三元一次方程：x+y-z=0 x+2y+z=13 2x-3y+2z=5x+y-z=0 x+2y+z=13 2x-3y+2z=5 三元一次方程x+y+z=0 4x+2y+z=3 9x+3y+z=6x+y+z=04x+2y+z=3 9x+3y+z=6