2x+7y-14=0
3x+y=2
pls
幫我解解e條用消元法做既方程
2007-02-24 3:05 am
回答 (2)
2007-02-24 3:12 am
✔ 最佳答案
2x+7y-14=0 －１3x+y=2 －２
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７（３ｘ＋ｙ）＝２（７）
２１ｘ＋７ｙ＝１４
２１ｘ＋７ｙ－１４＝０ －３
１－３，
２Ｘ＋７Ｙ－１４＝０
－）２１ｘ＋７ｙ－１４＝０
－－－－－－－－－－－－－
－１９Ｘ＝０
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代ｘ＝０入２，
３（０）＋ｙ＝２
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參考: ｍｅｍｅ
2007-02-24 7:46 am
Let :
2x+7y-14=0 .....(1)
3x+y=2 ....(2)
3*(1) - 2*(2)
=> 6x + 21y - 42 =0
- 6x + 2y = 4
_________________
19y -42 = -4
=> y = 2
Substitute y = 2 into (2)
3x + 2 = 2
=> x = 0
Therefore, x = 0 & y = 2 (Answer)
2x+7y-14=0 .....(1)
3x+y=2 ....(2)
3*(1) - 2*(2)
=> 6x + 21y - 42 =0
- 6x + 2y = 4
_________________
19y -42 = -4
=> y = 2
Substitute y = 2 into (2)
3x + 2 = 2
=> x = 0
Therefore, x = 0 & y = 2 (Answer)
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