x:y=1:5,y:z=2:3,x+y+z=27解这个2元一次方程组

x/2=y/3=z/5 x+3y-z/x-3y+z 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y= 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 方程组 (1) x+2y-3z=12 x-3y+2z= - 13 x-y-z=0 (2) x+ y=z 5x-y+z=18 2x+5y+3z= -1 x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) x+y+z=6 x+2y+3z=14 y+1=z {x+y+z=1 x-2y+3z=5 2x-3y-3z=-8 2x-y+3z=3 {3X+Y-2Z=-1 X+Y+Z=5 x-y+z=-1 5x+2y-z=6 4x-3y+2z=-5 x+y+z=-5,3x+y+z=1,4x+3y+2z=-2快 3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5