若2x-5y+4z=17,2x+10y+z=13,则x+y+z=?帮个忙,OK?

(4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-z)= 若2x-5y+4z=17,2x+10y+z=13,则x+y+z=?帮个忙,OK? 若3x-5y+4z=17,2x+10y+z=13,则x+y+z= 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 若x/2=y/3=z/4,则3x-2y+5z/x+y+z= -2X+3Y+Z=-4-X-5Y-2Z=-13X+Y-Z=10 x+y+2z=5 2x-y-z=4 3x+y-3z=10 {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 若4x=7y+5z,2x+y=z,则x:y:z的值为 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 三元一次方程组,1.x-2y+z=9 2x+y+3z=10 3x+2y1.x-2y+z=92x+y+3z=103x+2y-z2.3x-5y+2z=14x+5y-z=5X-5y+3z=-23.7x+2y-z=76x-y+z=74x+3y+z=94.4x+3y-2z=-75x-6y+z=12x+z=-25.2x+3y-4z=-23x-2y+5z=262x+5z=31 方程组{x/2+y/3-z=-5,x/3-y/2+z/2=10,x/2-y/3-z/4=6,求x,y,z 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z x+y-2z=5 2x-y-z=4 3x+y-3z=10；分别求x、y、z的值. 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.