{2x-y=7,{y十z=-5 {z-x= -7

{2x-y=7,{y十z=-5 {z-x= -7 解方程组 2x一y十3z=3 3x十y一2Z=-1 x十y十Z=5 {X+y+z=8,X一z=-2,y十z=1 解方程组 2x十y=2 2y十Z=7 x十2z=3 解方程组 2x十y=2 2y十z=7 x十2z=3 解方程：x十y十Z=4,2x一y十Z=3,3x一2y一3Z=-5, {x十y十z=12,x十2y一5z=22,3x-2y-4z=8 若1/X十2/y十3/z=5,3/X十2/y十1/z=7,则1/X十1/y十1/z=? {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z x十y=91,z十y=63,z十x=46求X,y,z x十y=91,z十y=63,z十x=46,求x,y,z x+y+z=14 7z=x+y+2 x+z=y x/2=y/3=z/5 x+3y-z/x-3y+z {3x一2y十z=4 {2x一y十2z=6 {X十y十Z=3急, 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) (x+y-z)(x-y+z)= fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14