X：Y=5：3,X：Z=7：3,2X—Y—Z=34.解方程组

x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z x/2=y/3=z/5 x+3y-z/x-3y+z 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) 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.. (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-1 x/5=y/3 x/7=z/3 2x-y-z=34 3x-y=-7,y+2z=2,2x-2z=-5 求x,y,z 5x+4y+z=0 3x+y-4z=13 x+y+z=—2 x+y+z=0,3x-2y-2z=5,y-z=2x-7 X-Y-Z=0 X+Y-3Z=4 2X-5Y+7Z=21 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 3x+7y+4z=35,x+5y+2z=40,x+y+z=( ) {x+y+z=1 {x+3y+7z=-1 {x+5y+8z=2 {x+y+z=1 {x+3y+7z=2 {x+5y+19z=4