送分!!? {2x+3y=5, 5x+9y=22
回答 (4)
2010-02-12 8:50 pm
✔ 最佳答案
x=-7, y=19/3
2010-02-12 10:27 pm
∴y=19/3, x=-7
2010-02-12 8:49 pm
{2x+3y=5-----[1]
5x+9y=22}-----[2]
[1]x(-3),
-6x-9y=-15-----[3]
[3]+[2],
-x=7
x=-7
代x=-7入[1]
2(-7)+3y=5
3y=19
y=19/3
所以x=-7,y=19/3
(已驗算正確)
5x+9y=22}-----[2]
[1]x(-3),
-6x-9y=-15-----[3]
[3]+[2],
-x=7
x=-7
代x=-7入[1]
2(-7)+3y=5
3y=19
y=19/3
所以x=-7,y=19/3
(已驗算正確)
參考: 自己
2010-02-12 8:48 pm
2x+3y = 5 ----------(1)
5x+9y = 22 --------(2)
(1) x 3
6x + 9y = 15 ------(3)
(2) - (3)
5x + 9y - 6x - 9y = 22-15
-x = 7
x = -7
Put x = -7 into (1)
2(-7) + 3y = 5
3y = 5+14
y = 19/3 = 6.333
5x+9y = 22 --------(2)
(1) x 3
6x + 9y = 15 ------(3)
(2) - (3)
5x + 9y - 6x - 9y = 22-15
-x = 7
x = -7
Put x = -7 into (1)
2(-7) + 3y = 5
3y = 5+14
y = 19/3 = 6.333
參考: 自己
收錄日期: 2021-04-13 17:05:17
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