x+2y-7z=0 x=-2y+7z 2x=-4y+14z
由4x-3y-6z=0,x+2y-7z=0
得5x-y-13z=0 则5x=13z+y
所求5x+2y-z/2x-3y-10z=13z+y+2y-z/-4y+14z-3y-10z=12z+3y/-7y+4z
x=-2y+7z 5x=-10y+35z
又∵ 5x=13z+y
∴-10y+35z=13z+y
解得y=2z
5x+2y-z/2x-3y-10z=12z+3y/-7y+4z=18z/-10z=-9/5