若x:y:z=3:4:7,且2x-y+z=18,求代数式x+2y-z的值.
若x:y:z=3:4:7,且2x-y+z=18,求代数式x+2y-z的值.
已知x:y:z=2:3:4,且x+y+z=18,求x,y,z的值
若2分之x+y=3分之y+z=5分之x+z 且x+y+z=18 求x,y,z的值
若x-y=6,xy=-8,求代数式(x+y+z)²+(x-y-z)(x-y+z)-2·z(x+y)的值
已知x:y:z=2:3:4,且x-y+z=36,求x+y+z的值.
已知x+y/2=y+z/3=z+x/4,且x+2y+z=12,求x-2y+z的值
已知x/2=y/3=z/4,且x+y+z不等于0,求2x+3y-4z/x+y+z的值
若z≠0,且4x=7y+5z,2x+y=z,求x,y,z的值
若4x-3y-6z=0,x+2y-7z=0,求代数式5x*5x+2y*2y-z*z/2x*2x-3y*3y-10z*10
已知4x-3y-6z=0,x+2y-7z=0,且x、y、z都不为0,求(3x+2y+z)/(x+2y+3z)的值 快帮求
已知4x-3y-6z=0 ① ,x+2y-7z=0 ②,且x,y,z均不为0,求3x+2y+z÷x+2y+3z的值
已知4x-3y-6z=0,x+2y-7z=0,且x,y,z≠0,求2x+3y+6z/x+5y+5z的值.