x+2y+3x=15,x-y+7x=20,x+3y+2z=14

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x+2y+3x=15,x-y+7x=20,x+3y+2z=14
改下是x+2y+3z=15，x-y+7z=20，x+3y+2z=14

题目确定如此,不再更改?
再问：好吧打错了……
x+2y+3z=15，x-y+7z=20，x+3y+2z=14
再答： x+2y+3z=15①
x-y+7z=20②
x+3y+2z=14③
①+②×2
3x+17z=55④
②×3+③
4x+23z=74⑤
⑤×3-④×4
69z-68z=222-220
z=2
代z=2入④
3x+17×2=55
x=7
代x=7；z=2入②
7-y+14=20
y=1
即：方程组的解为x=7；y=1；z=2

试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) x/2=y/3=z/5 x+3y-z/x-3y+z x+2y=3 x+y+z=36 2x+y+z=15 2y=3z x-y=1 x+2y+z x-z=-1 2x+z-y=1 x+2y+3z=14 2x+y+z=7 3x+y+2z=11 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, x+2y+3z=14 2x+y+z=7 3x+y+2z=11 求x y z 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 x-2y=9 x+y+z=7 2x-3y=12 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=- 已知20（x+2y）=15（y+3Z)=12（z+5x),则x:y