國二…工程問題:－線上遊戲排行榜2013/2014,進擊的巨人線上看,candy crush saga外掛,正妹寫真三圍

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國二…工程問題

Dec 27th 2013, 05:23

甲、乙兩人合作一工程x天可完成，比甲獨作早12天完成，比乙獨作早27天
完成，求甲、乙獨作各需幾天完工?
Sol
甲獨作x+12天完成
乙獨作x+27天完成
So
1/(x+12)+1/(x+27)=1/x
x(x+27)+x(x+12)=(x+12)(x+27)
2x^2+39x=x^2+39x+324
x^2－324=0
(x－18)(x=18)=0
x=18 or x=－18(不合)
甲獨作30天完成
乙獨作45天完成

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