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freeze3704 2011-09-15 18:30

Maths help!

Cut a rectangular piece of iron with an area of 150cm2 and its length is 5cm longer than its width.What are the width and length of this pece of iron?
steps and answer thx

happyless 2011-09-15 18:36
引用樓主freeze3704於2011-09-15 18:30發表的 Maths help! :
Cut a rectangular piece of iron with an area of 150cm2 and its length is 5cm longer than its width.What are the width and length of this pece of iron?
steps and answer thx

最差數學 恕我無能

勇氣誓言 2011-09-15 18:47
L x W=150
L=W+5

(W+5)W=150
W^2+5W-150=0
(W+15)(W-10)=0
W=10 L=15
這是中一嗎？ 囧
其實1d 都5深- -

freeze3704 2011-09-15 18:53
引用第2樓勇氣誓言於2011-09-15 18:47發表的  :
L x W=150
L=W+5
(W+5)W=150
W^2+5W-150=0
.......


伏已中369

waynewong 2011-09-15 19:46
引用第3樓freeze3704於2011-09-15 18:53發表的  :
伏已中369

下我想問有咩錯?
係咪3D?有height?_?

bk的卓男 2011-09-15 19:56
Cut a rectangular piece of iron with an area of 150cm2 and its length is 5cm longer than its width.What are the width and length of this pece of iron?
steps and answer thx

此數學題無法計算

Let the length be x cm and the width be y cm
xy = 150   ........(1)
x - y = 5   .........(2)

From (2): x = 5+y  ..........(3)

Put (3) into (1):
y(5+y) = 150
5y + y² = 150
y² + 5y - 150 = 0
y = 10 or y = -15(rej.)
∵y  = 10
∴ x = 15
∴The required length and width are 15cm and 10cm respectively



求伏

waynewong 2011-09-15 19:58
引用第5樓bk的卓男於2011-09-15 19:56發表的  :
Cut a rectangular piece of iron with an area of 150cm2 and its length is 5cm longer than its width.What are the width and length of this pece of iron?
steps and answer thx
此數學題無法計算
.......

一早留意到呢個錯字 ._. 唔會影響到你既

勇氣誓言 2011-09-15 20:03
引用第6樓waynewong於2011-09-15 19:58發表的  :
一早留意到呢個錯字 ._. 唔會影響到你既

仲以為樓主打錯字
原來有心昆人:(

freeze3704 2011-09-15 20:32
i also answer 15 and 10
but it is wrong
so i ask- -

202202 2011-09-15 20:38
你系咪調轉左10同15啊-.-?

bk的卓男 2011-09-15 20:49
引用第8樓freeze3704於2011-09-15 20:32發表的  :
i also answer 15 and 10
but it is wrong
so i ask- -

你邊到睇答案嫁

一係答案錯
一係你阿sir改錯
一係就

數學已有全新革命  最新最岩既計算方法與現時我地學既完全不一

waynewong 2011-09-15 20:50
引用第10樓bk的卓男於2011-09-15 20:49發表的  :
你邊到睇答案嫁
一係答案錯
一係你阿sir改錯
.......

可能阿sir唔係阿sir :o)

qqwess 2011-09-15 22:10
呢d題目有九成都唔係計錯

係寫漏單位

有無寫 cm落去

無好似當錯

bk的卓男 2011-09-15 23:10
引用第12樓qqwess於2011-09-15 22:10發表的  :
呢d題目有九成都唔係計錯
係寫漏單位
有無寫 cm落去
.......

單位錯扣一分

唔該上堂多d叫你阿sir講下d 計分方法

qqwess 2011-09-15 23:24
引用第13樓bk的卓男於2011-09-15 23:10發表的  :
單位錯扣一分
唔該上堂多d叫你阿sir講下d 計分方法

不需理會

這麼簡單的東西

填左就唔洗理扣分啦

（我中四）

bk的卓男 2011-09-16 00:01
引用第14樓qqwess於2011-09-15 23:24發表的  :
不需理會
這麼簡單的東西
.......

你以為每一個你都咁易睇到係乜單位?

最陰既係 以"單位" 作單位既題目
姐係答案你要寫係
某數 單位
咁樣
呢類型既永遠好多人都會死

你講到好咁易咁
讀到英文你見到成炸雞腸就知死

dwchan 2011-09-16 04:13
let the width be X

Length=X+5

X(X+5)=150
X2+5X-150=0
X=10 OR -15(reji)

width=10

Length=10+5=15

bk的卓男 2011-09-16 21:07
引用第16樓dwchan於2011-09-16 04:13發表的  :
let the width be X
Length=X+5
X(X+5)=150
.......

冇單位扣分:D

aesopq159357 2011-09-17 23:33
數學我最差,help你唔到==

火閃電 2011-09-17 23:38
引用第18樓aesopq159357於2011-09-17 23:33發表的  :
數學我最差,help你唔到==

知你差 但係你唔駛講出黎


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