已知x:y:z=3:4:5 ⑴求X+Y/Z的值 ; 二X+Y+Z=6,求2X-Y+3Z的值谁好选谁

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已知x:y:z=3:4:5 ⑴求X+Y/Z的值 ; 二X+Y+Z=6,求2X-Y+3Z的值谁好选谁
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已知x:y:z=3:4:5 ⑴求X+Y/Z的值 ; 二X+Y+Z=6,求2X-Y+3Z的值谁好选谁
已知x:y:z=3:4:5 ⑴求X+Y/Z的值 ; 二X+Y+Z=6,求2X-Y+3Z的值
谁好选谁

已知x:y:z=3:4:5 ⑴求X+Y/Z的值 ; 二X+Y+Z=6,求2X-Y+3Z的值谁好选谁
x:y:z=3:4:5
所以设x=3m,y=4m,z=5m
(x+y)/z=(3m+4m)/5m=7/5
因为2x+y+z=6m+4m+5m=15m=6
所以m=2/5
2x-y+3z=6m-4m+15m=17m=34/5

⑴X+Y/Z=7/5
[2]x:y:z=3:4:5
X+Y+Z=6
x=3*6/12=3/2
y=4*6/12=2
z=5*6/12=5/2
2X-Y+3Z=2*3/2-2+3*5/2=3-2+15/2=17/2或8.5