x-2y=4 3x-3y-2z=1 x+y+z=5

x/2=y/3=z/5 x+3y-z/x-3y+z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=- x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y- 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z. x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, x+y+z=2 4x+2y+z=4 2x+3y+z=1 已知3x=4y,2y=5z,试求x:y:z