解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可变形为X/1=Y/2=Z/3)

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解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可变形为X/1=Y/2=Z/3)
解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可
解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.
(提示:X:Y:Z=1:2:3可变形为X/1=Y/2=Z/3)

解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可解方程组;{X:Y:Z=1:2 :3,X+Y+Z=36.(提示:X:Y:Z=1:2:3可变形为X/1=Y/2=Z/3)

解由
X:Y:Z=1:2 : 3
即X/1=Y/2=Z/3
设X/1=Y/2=Z/3=k
则X=k,Y=2k,Z=3k
又由
X+Y+Z=36
得k+2k+3k=36
即6k=36
解得k=6
故X=6,Y=12,Z=18

设X/1=Y/2=Z/3=K
则X=K,Y=2K,Z=3K
所以K+2K+3K=36
6K=36
K=6
所以X=6,Y=2X6=12,Z=3X6=18
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由x:y=3得,x=3y;由y:z=1:5得,z=5y
把x=3y z=5y代人x+y+z=27中得,3y+y+5y=27,∴y=3,从而x=9 z=15
①-③得,-2x-y=2……④,
①×2+②得,3x-y=13……⑤
⑤-④得,5x=11,解得x=2.2,从而y=-6.4,z=-10.2
(0.4x-10)/0.4-(5-x)/2≤(0.03-...

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由x:y=3得,x=3y;由y:z=1:5得,z=5y
把x=3y z=5y代人x+y+z=27中得,3y+y+5y=27,∴y=3,从而x=9 z=15
①-③得,-2x-y=2……④,
①×2+②得,3x-y=13……⑤
⑤-④得,5x=11,解得x=2.2,从而y=-6.4,z=-10.2
(0.4x-10)/0.4-(5-x)/2≤(0.03-0.02x)/0.03
x-25-(5-x)/2≤(3-2x)/3
6x-150-15+3x≤6-4x
6x+3x+4x≤150+15+6
13x≤171
x≤171/13

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