已知xyz不等于0,且2x-y+z=0,x-2y+3z=0,求代数式(x²+3y²+5z²)/(2x²+4y²+7z²)的值

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的值为? 已知xyz不等于0,且x+2y-z=0,7x-y-z=0,求x+y+z/2x-y-z的值. 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 已知xy/5=y+z/6=z+x/7,且xyz不等于0,求x:y:z 已知方程组2x-3y+z=0 3x-2y-6z=0 且xyz不等于0求 x:y:z 已知方程组x-3y-2z=0,2x-y+z=0,且xyz不等于0,求x：y:z. 已知4x-5y+2z=0,x+4y-3z=0 且xyz不等于0,求x:y:z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=最好有过程 已知x/2=Y/3=Z/4且xyz不等于0,求2X+3Y-Z/X-3Y+Z的值. 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-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的值. 代数式的恒等变形3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)(y+z）(z+x)/xyz的值 已知xyz不等于0,且{x+3y+5z=0 x2+3y+z=0,则x.x+y.y-2z.2z/3x.3x+2y.2y+z.z=? 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? 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,且满足(y+z)/x=(x+z)/y=(x+y)/z,求（y+z)（x+z)（x+y)/xyz的值 已知4x-5y+2z=0,且x+4y-3z=0,(xyz不等于0）试求x/y 已知4x-5y+2z=0,且x+4y-3z=0,(xyz不等于0）试求x/y