若2x+3y-4z=7.则x+3y-5z=2.则x+2y-3z的值为

若x/2=y/3=z/4,则3x-2y+5z/x+y+z= 若x+y+z=3y=2z,则x/x+y+z=? 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 三元一次方程组题目x+y-z=11 y+z-x=5 x-y+z=1x+y=4 y+z=3 x+z=5若已知x-3y+2z=0 2x+3y-8z=0, 且xyz≠0,则x:y:z= 若3x+7y+z=5,4x+10y+z=3,则x+y+z=? 若x/3=y/2=z/5,则2x-3y-z/x-y+z= 若2x=3y=5z,则3x-2y+z/x+y-z 已知(x+2y)/3=(y+3z)/4=(z+5x)/5,则x:y:z= 已知x+2y/3=y+3z/4=z+5x/5,则x:y:z=? 已知x+2y/3=y+3z/4=z+5x/5,则x:y:z= 若x+y:y+z:z+x=3:4:5,则x:y:z=?(急,) 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 已知x+4y-3z=0,4x-5y+2z=0,则x：y：z 已知x+4y=3z,4x-5y=-2z,则x:y:z 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 已知2x+5y+4z=15.7x+y+3z=14 则x+y+z=? 若x/2=y/3=z/4则3x-2y+5z/x+y+x= 若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z