代數方法解聯立方程
{x²-2y²=1
{3x+4y=1
聯立方程代數
2014-01-12 12:06 pm
回答 (1)
2014-01-12 4:04 pm
✔ 最佳答案
3x + 4y = 1x = (1 - 4y)/3
x^2 = (1 - 4y)^2/9
Sub. into the other equation,
(1 - 4y)^2/9 - 2y^2 = 1
(1 - 4y)^2 - 18y^2 = 9
1 + 16y^2 - 8y - 18y^2 = 9
2y^2 + 8y + 8 = 0
y^2 + 4y + 4 = 0
(y + 2)^2 = 0
y = - 2.
x = [ 1 - 4(-2)]/3 = (1 + 8)/3 = 3.
收錄日期: 2021-04-25 22:50:55
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20140112000051KK00021