x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=?

1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? 三元一次方程 X-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 X=?Y=?Z=? x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 {x+y-z=11 y+z-x=5 z+x-y=1 {x+y-z=11,x-y-z=-5,x-y+z=1 ..1.x+y+z=26,2.4y+3z=7,y-z=1,3x+2z=17,x+2y-z=18 9x-7y=173.x-7y+3z=17 4.2x+4y+3z=95x-6y-z=24 3x-2y+5z=113x+7y-2z=1 5x-6y+7z=131.x+y+z=26,y-z=1x+2y-z=18 2.4y+3z=7,3x+2z=11,9x-7y=17 3.x-7y+3z=17 5x-6y-z=24 3x+7y-2z=14.2x+4y+3z=93x-2y+5z=11 5x-6y+7z=13 (1)2X+4Y+3Z=93X-2Y+5Z=115X-6Y+7Z=13(2)X:Y=3:2Y:Z=5:4X+Y+Z=66(3)3X-Y+Z=32X+Y-3Z=11X+Y+Z=13以上3个题目为三元一次方程~ 六年级三元一次方程组第一题：{5x-3y+z=2 5x+2y-4z=3 -5x+y-z=2第二题：{x+y=-2 x+z=13 y+z=1第三题：{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 {x+y+z=1 {x+3y+7z=-1 {x+5y+8z=2 {x+y+z=1 {x+3y+7z=2 {x+5y+19z=4 {x-y-z=-1 {3x+5y +7z=11 {4x-y+2z=-1 求X,Y, 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-1 2x+3y-z=11 2x+y-5z=8 -2+7y+z=19 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z.