x+3y=7 y+3z=8 z+3x=5解这个三元一次方程,可得到x+y+z=

x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 {x+y+z=1 {x+3y+7z=-1 {x+5y+8z=2 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 已知关于x y z的方程组2x-3y+5z=7 x+2y-3z=8,则4x+y-z= x/2=y/3=z/5 x+3y-z/x-3y+z 已知:x+y+z=0,5x-3y-z=0,求:5x-y+z/2x+8y+7z 的值 三元一次方程组2x+z=3 3x+y-z=8 x+3y+2z=3 5x+2y-3z=2 x+2y+z=6 7x-2y-4z=262x+z=3 3x+y-z=8 x+3y+2z=3 5x+2y-3z=2 x+2y+z=6 7x-2y-4z=26 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 2x+3y-z=11 2x+y-5z=8 -2+7y+z=19 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) x+y+z=1 x+3y+7z=-1 x+5y+8=2题错了 x+y+z=1 x+3y+7z=-1 x+5y+8z=2 X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) (x+y):(y+z):(z+x)=3:4:5 3x+y-z=-4已知(x+y):(y+z):(z+x)=3:4:5 ；3x+y-z=-4求x y z