x+y+z=15 2x+3y+4z=47 3x+4y+5z=62

x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 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) 4x-5z=17 3x+y+15z=18 x+2y+3z=2 求三元一次方程组特殊解法x+y+z=15 2x+3y+4z=47 3x+4y+5z=62 x+y+z=15 2x+3y+4z=47 3x+4y+5z=62 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 已知x:y:z=3:4:5,3x+2y-4z=18.求：x+y+z. {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 2x+5y+4z=0,3x+y-7z=0,则x+y-z=?