送分!! {2x+3y=5, 5x+9y=22
回答 (2)
2010-02-12 8:54 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
2010-02-12 8:54 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
2010-02-12 14:26:15 補充：
∴y=19/3, x=-7
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
2010-02-12 14:26:15 補充：
∴y=19/3, x=-7
收錄日期: 2021-04-13 17:05:44
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