中一數學急

2009-12-04 5:24 am

展開下列各式，需詳細列明步驟。
1. (2s-3)4s
2. (2y-5)(y+7)
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回答 (7)

2009-12-04 5:30 am

✔ 最佳答案

1. (2s-3)4s
=4s(2s)-4s(3)
=8s2-12s

2. (2y-5)(y+7)
=2y2+14y-5y-35
=2y2+9y-35

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2009-12-04 7:25 am

(2s)(4s)-3(4s)
=8s^2-12s

(2y)(y)+7(2y)-5y-35
=2y^2+14y-5y-35
=2y^2+9y-35

參考: myself

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2009-12-04 6:59 am

(2s-3)4s
=8s^2-12s

(2y-5)(y+7)
=2y^2-5y+14y-35
=2y^2+9y-35

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2009-12-04 6:08 am

1) 4s(2s-3)
=8s^2 - 12s

2) (2y-5)(y+7)
=2y(y+7) - 5(y+7)
=2y^2 + 14y -5y +35
=2y^2 + 9y + 35

參考: mine

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2009-12-04 5:38 am

(2s-3)4s
=4s(2s)-4s(3)
=8s2-12s

(2y-5)(y+7)
=2y2+14y-5y-35
=2y2+9y-35

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2009-12-04 5:33 am

1. (2s-3)4s
=8s-12s
=-4s

2.(2y-5)(y+7)
=2y square+14y-5y-35
=2y square+9y-35

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2009-12-04 5:29 am

(2s-3)4s
=6s*2-12s

(2y-5)(y+7)
=2y*2-5y+14y-35
=2y*2+9y-35

2009-12-03 21:33:47 補充：
sorry!!
(2s-3)4s
=8s*2-12s

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