Linear equations in two unknowns
(Steps Please)
6x- y-4/3 =10
y+ 3x-7/4 =1
Linear equations
2012-09-04 3:14 am
回答 (3)
2012-09-04 9:02 am
✔ 最佳答案
Case I :(6x - y - 4)/3 = 10 ...... [1]
(y + 3x - 7)/4 = 1 ...... [2]
From [1] :
6x - y - 4 = 30 ...... [3]
From [2] :
y + 3x - 7 = 4 ...... [4]
[3] + [4] :
9x - 11 = 34
9x = 45
x = 5
Put x = 5 into [4] :
y + 3(5) - 7 = 4
y = -4
Hence, x = 5 and y = -4
Case II :
6x - y - (4/3) = 10 ...... [1]
y + 3x - (7/4) = 1 ...... [2]
[1] + [2] :
9x - (16/12) - (21/12) = 11
9x = 169/12
x = 169/108
Put x = 169/99 into [2] :
y + 3(169/108) - (7/4) = 1
y = -35/18
Hence, x = 169/108 and y = -35/18
參考: 賣女孩的火柴
2012-09-06 6:33 am
Wai Ching 的答案 (002) 真是慳水慳力，把人家辛苦計來的答案 copy and paste，只把 Case I 改成 Firstly，把 Case II 改成 Secondly。
嚴格來說，002 的答案是錯誤的，因為 Firstly 和 Secondly 是指同一答案的兩部份，而不是兩個不同的情況。
嚴格來說，002 的答案是錯誤的，因為 Firstly 和 Secondly 是指同一答案的兩部份，而不是兩個不同的情況。
2012-09-06 2:17 am
Firstly,
(6x - y - 4)/3 = 10 ...... [1]
(y + 3x - 7)/4 = 1 ...... [2]
From [1] :
6x - y - 4 = 30 ...... [3]
From [2] :
y + 3x - 7 = 4 ...... [4]
[3] + [4] :
9x - 11 = 34
9x = 45
x = 5
Put x = 5 into [4] :
y + 3(5) - 7 = 4
y = -4
Hence, x = 5 and y = -4
Secondly,
6x - y - (4/3) = 10 ...... [1]
y + 3x - (7/4) = 1 ...... [2]
[1] + [2] :
9x - (16/12) - (21/12) = 11
9x = 169/12
x = 169/108
Put x = 169/99 into [2] :
y + 3(169/108) - (7/4) = 1
y = -35/18
Hence, x = 169/108 and y = -35/18
(6x - y - 4)/3 = 10 ...... [1]
(y + 3x - 7)/4 = 1 ...... [2]
From [1] :
6x - y - 4 = 30 ...... [3]
From [2] :
y + 3x - 7 = 4 ...... [4]
[3] + [4] :
9x - 11 = 34
9x = 45
x = 5
Put x = 5 into [4] :
y + 3(5) - 7 = 4
y = -4
Hence, x = 5 and y = -4
Secondly,
6x - y - (4/3) = 10 ...... [1]
y + 3x - (7/4) = 1 ...... [2]
[1] + [2] :
9x - (16/12) - (21/12) = 11
9x = 169/12
x = 169/108
Put x = 169/99 into [2] :
y + 3(169/108) - (7/4) = 1
y = -35/18
Hence, x = 169/108 and y = -35/18
參考: me
收錄日期: 2021-04-13 18:57:07
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120903000051KK00585