y=x+z,y-x=2,x+10y+100z+99=z+10y+100x,联立这三个等式,答案是：x=3,y=5,z=2,算来算去不对,帮帮忙啊,要过程

(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 3X+2y+z=20 x+y+z=10 Y=3X {2x+y=10 {x-y+z=4 {3x-y-z=0 解方程 Y=X+Z Y-Z=2 100Z+10Y+X-(100X+10Y+Z)=99 Y=X+ZY-Z=2100Z+10Y+X-(100X+10Y+Z)=99 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 解方程组：{x(x+y+z)=6 {y(x+y+z)=9 {z(x+y+z)=10 X=3z X+y+z=12 X+2y-2z=10 2x+z=10 x+y-z=4 3x-y-z=0 10X+Y+1/3Z=10Y+X 10X+Y+2/3Z=100X+Y x+y=8 y+z=12 x+z=10 x+y+z= x+y=8 y+z=12 x+z=10 x+y+z= x+y+z=15 x+5y+10z=70 x,y,z,各是几? x+y+z=15 x+5y+10z=70 x,y,z,各是几? X+Y-Z=15 X+5Y+10Z=70 求：X、Y、Z (x+y-z)(x-y+z)= 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证?