4x+5y=1......(1)
2x-y+3=0......(2)
x=-1
y=1
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聯立2元1次問題
2007-09-20 11:29 pm
回答 (2)
2007-09-21 12:01 am
✔ 最佳答案
equation 1: 4x + 5y = 1equation 2: 2x - y + 3 = 0
if equation 1 - 2 * equation 2, then
(4x + 5y) - 2 * (2x - y + 3) = (1) - 2 * (0)
(4x - 2 * 2x) + [5y - 2 * (-y)] - 2 * 3 = 1
7y - 6 = 1
7y = 7
y = 1
then put y = 1 into either equation 1 or equation 2, you can get
x = -1
2007-09-21 12:02 am
4x+5y=1......(1)
2x-y+3=0......(2)
(2) * 2: 4x - 2y + 6 = 0 ......(3)
(1) - (3): 7y - 6 = 1
7y = 7
y=1
Sub y=1 into (2): 2x - 1+ 3 = 0
x = -1
2x-y+3=0......(2)
(2) * 2: 4x - 2y + 6 = 0 ......(3)
(1) - (3): 7y - 6 = 1
7y = 7
y=1
Sub y=1 into (2): 2x - 1+ 3 = 0
x = -1
收錄日期: 2021-04-23 17:18:05
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070920000051KK01507