有關數學一問~~~

2006-12-09 4:37 am

有冇人可以講比我知點解呢條數點樣計(方程)︰
a - 0.3a = 500
a = ?

答下我啦，please！
(同埋可唔可以講比我聴點解係咁計)

回答 (7)

2006-12-09 5:42 am

✔ 最佳答案

你有唔同既方法去做:
1)
a - 0.3a = 500
0.7a = 500
a = 500/0.7
a = 5000/7

2)
10(a - 0.3a) = 10(500)
10a - 3a = 5000
7a = 5000
a = 5000/7

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2006-12-09 6:35 am

a-0.3a=500
(1-0.3)a=500
0.7a=500
a=500/0.7
a=714.28.......
a=714(corr. to 3 sig. fig.)

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2006-12-09 5:15 am

a - 0.3a = 500
a-0.3a=0.7a
500=0.7a
71.42855....=0.1a
a=71.42855x10=714.2855

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2006-12-09 4:46 am

a - 0.3a = 500
1a - 0.3a = 500 ----a=1a
(1 - 0.3)a= 500 ----抽出
0.7a = 500
a = 500/0.7 ----調過去除
a = 714.28571....

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2006-12-09 4:45 am

a - 0.3a = 500

0.7a=500

a=500/0.7

a=7142 6
---
7

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2006-12-09 4:44 am

a-0.3a=500
0.7a=500(等於1-0.3)
a=500/0.7
a=七又四分之一(唔識打出黎)

2006-12-08 20:44:58 補充：
*七又七分之一

參考: 自己計

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2006-12-09 4:43 am

a-0.3a = 500
0.7a =500
a =500/0.7

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