若3x+4y+5z=17,3x+2y+z=13,则x+y+z= ）

若x/2=y/3=z/4,则3x-2y+5z/x+y+z= 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? x/2=y/3=z/5 x+3y-z/x-3y+z 若x+y+z=3y=2z,则x/x+y+z=? x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值 ..1.x+y+z=26,2.4y+3z=7,y-z=1,3x+2z=17,x+2y-z=18 9x-7y=173.x-7y+3z=17 4.2x+4y+3z=95x-6y-z=24 3x-2y+5z=113x+7y-2z=1 5x-6y+7z=131.x+y+z=26,y-z=1x+2y-z=18 2.4y+3z=7,3x+2z=11,9x-7y=17 3.x-7y+3z=17 5x-6y-z=24 3x+7y-2z=14.2x+4y+3z=93x-2y+5z=11 5x-6y+7z=13 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 4X+9Z=12 {3Y-2Z=17X+5Z=4又4分之33X-Y+2Z=3{2X+Y-3Z=11X+Y+Z=66 x+y=5 2x+3y-z=9 x-y+z=4 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) 1.若3x-2y+z=2;3x+2y+5z=4,求x+22.若x-3y+z=0;3x-3y-4z=0,求x:y:z 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 三元一次方程组题目x+y-z=11 y+z-x=5 x-y+z=1x+y=4 y+z=3 x+z=5若已知x-3y+2z=0 2x+3y-8z=0, 且xyz≠0,则x:y:z=