几道预初数学题 急1.3x-2y=m2x+3y=m 则x：y=2.xyz不等于0.4x-5y+2z=0x+4y-3z=0

已知方程组4x-y+3z=0 2x+y+6z=0且xyz不等于0,则x/y+y/z+z/x是多少 方程组:x-2y+4z=0,2x+3y-3z=0...xyz不等于0,求(2x+y-z)\(2x-y+z) 已知4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值 已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz 已知x+4y-3z=0,4x-5y+2z=0(xyz不等于0),则x:y:z=? 已知:(x+y)/z=(x+z)/y=(z+y)/x,且xyz不等于0,则分式(x+y)(x+z)(z+x)/xyz的值 已知方程组4x-y+3z=0,2x+y+6z=0.且xyz不等于0,则x:y:z= 若xyz不等于0,且{4x-5y+2z=0,x+4y-3z=0,求x:y:z 已知xyz不等于0,且x/3=y/4=z/5,求【2x-3(2y-z)】/x+y+z 已知x+y-7z=0 x-2y+5z=0(xyz不等于0）,求x+2y-z/y-2x+12z 若xyz不等于0,且满足(y+z)/x=(x+z)/y=(x+y)/z,求（y+z)（x+z)（x+y)/xyz的值 若xyz不等于0,且(y+z)/x=(z+x)/y=(x+y)/z,求(y+z)(z+x)(x+y)/xyz的值?