如何证明x：y=3：5,y：z=2:3则x:y:z=6:10:15?

试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 x/2=y/3=z/5 x+3y-z/x-3y+z 若{x+3y+10z=0 则 (x+y-z)/(x-y+z) 试证明(x+y-2z)³+(y+z-2x)³+(z+x-2y)³=3(x+y-2z)(y+ (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 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 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 证明:(y+z-2x)^3+(z+x-2y)^3+(x+y-2z)^3=3(y+z-2x)(z+x-2y)(x+y-2z 证明：（y+z-2x）3+（z+x-2y）3+（x+y-2z）3=3（y+z-2x）（z+x-2y）（x+y-2z）． 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, x+y+z=4 2x+3y-z=6 3x+2y+2z=10