z+y=3x,3x-9=y-1,5y-5=3x-7

{5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=- x/2=y/3=z/5 x+3y-z/x-3y+z 解方程一;{x+y-z=6,x-3y+2z=1,3x+2y-z=-7.②{3x+4z=7,2x+3y+z=9,5x-9y x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 设变量xy满足 x+y-3 x-y+1 3x-y+5 z=x+y/x （1）3x+4z=7;2x+3y+z=9;5x-9y+7z=8 (2)3x+4y+z=14;x+5y+2z=17;2x+ 已知5x=3y,4z=7y,求x:y:z 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 已知3X=4X,5Y=6Z求X+Y：Y+Z 已知5x+3y+1/3z=100 7x+y+z=100 那么x+y=?