負負得正(--=+)

👨🏻‍🏫 學術台數學

LawSamuel

2007-12-01 6:44 am

負負得正why????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

回答 (9)

用戶109657

2007-12-01 7:23 am

✔ 最佳答案

你咁諗,
一班十人, 五個好學生(+), 五個壞學生(-),

加左一個好學生, 成班變好, 正正得正
加左一個壤學生, 成班變差, 正負得負
少左一個好學生, 成班變差, 負正得負
少左一個壤學生, 成班變好, 負負得正

明未a X)

唔明可以試下用借貸諗~

👍 0 👎 0

chunkinchoi

2007-12-02 10:41 pm

Someone have -1dollar means he borrow 1 dollar.If he have --1dollar,it means another one borrow him 1dollar and he(someone) borrow another one 1 dollar.So someone have 1 dollar.It is 負負得正!(example)

👍 0 👎 0

Pinky

2007-12-01 8:46 pm

你要記住
逢親有1個正,答案就係另外果個 (正正-->正正負-->負)
逢親有1個負,如果另外果個係正,答案係負;如果另外果個係負,答案係正 (負負-->正負正-->負)

所以負負得正

參考: myself

👍 0 👎 0

Descartes

2007-12-01 8:21 am

Additive Inverse
a+(-a)=0 for some real a

Now , a+(-a)+[-(-a)]=[-(-a)]
a=[-(-a)] ( (-a)+[-(-a)]=0 )

👍 0 👎 0

hiu fung

2007-12-01 7:36 am

因為有分配律

我睇一本有關數學的書
佢係咁講....

a x 0 = 0

假設

a = -2
0 = 3 -3

a x 0 = 0

*(-2) x (3 -3)* = (-2) x 3 +(-2) x (-3)

打*果舊野 = 0

*(-2)x 3* + (-2)x (-3) = 0
* -6* +(-2)x (-3) = 0

最後將個-6移去右邊

* (-2) x (-3) = 6 *

大功告成!!!

參考: 圖解數學基礎入門 (公共圖書館有得借)

👍 0 👎 0

用戶184713

2007-12-01 7:14 am

+(+)=+因為兩個都是一樣,是+ -(-)=+ 因為兩個都是一樣-

+( - )= -因為正負是兩個都不同 -(+)=-因為負正是兩個都不同

就讀:Lam Tai Fai College 年級:F1

e-mail:[email protected]
msn:chanchan8820012003hotmail.com

👍 0 👎 0