(x)(y)=88-------(1)
2x+2y=38-----(2)
求x同y既值
中學數學...急!!!!
2007-09-23 6:06 am
回答 (4)
2007-09-23 6:14 am
✔ 最佳答案
xy=88---(1)2x+2y=38---(2)
. x+ y=19
. x=19-y---(3)
sub (3) into (1)
(19-y)y=88
19y-y^2-88=0
y=8 or 11
sub y=8 into (1)
. x=11
sub y=11 into (1)
. x=8
ANS: y=8,x=11 or y=11,x=8
參考: 自己
2007-09-23 6:15 am
x y = 88 --------(1)
2x+2y =38
=> x+y = 19 -------(2)
sub (2) into (1)
x(19-x) = 88
x^2 - 19x +88 = 0
(x - 8) (x-11) = 0
x =8 or 11
When y = 11, x =8 or When x = 11, y =8
2x+2y =38
=> x+y = 19 -------(2)
sub (2) into (1)
x(19-x) = 88
x^2 - 19x +88 = 0
(x - 8) (x-11) = 0
x =8 or 11
When y = 11, x =8 or When x = 11, y =8
參考: My calculation
2007-09-23 6:15 am
from (2),
x=19-y...(3)
put(3)into(1),
(19-y)y=88
y^2-19y+88=0
y=8 or 11
when y=8,x=11
when y=11,x=8
x=19-y...(3)
put(3)into(1),
(19-y)y=88
y^2-19y+88=0
y=8 or 11
when y=8,x=11
when y=11,x=8
參考: 自己=]
2007-09-23 6:11 am
From(1),
x=88/y----------(3)
Put(3)into(2),
2(88/y)+2y=38
176/y+2y=38
176+2y²=38y
y²-19y+88=0
(x-11)(x-8)=0
x=11 or 8
x=88/y----------(3)
Put(3)into(2),
2(88/y)+2y=38
176/y+2y=38
176+2y²=38y
y²-19y+88=0
(x-11)(x-8)=0
x=11 or 8
參考: ME
收錄日期: 2021-04-13 13:36:10
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https://hk.answers.yahoo.com/question/index?qid=20070922000051KK05118