the equation of the line L is
(2k2-7k+3)x+(9-k2)y+3k2=0
where k is constant. If the y-intercept of L is 4, find the equation of L.
F.4 AM Straight Line
2008-06-17 5:34 am
回答 (2)
2008-06-17 5:45 am
✔ 最佳答案
If the y-intercept of L is 4, it means that L passes through (0,4).Putting x=0,y=4
(2k^2-7k+3)(0)+(9-k^2)(4)+3k^2=0
36-4k^2 3k^2=0
k^2 = 36
k = 6 or -6
Putting k into L, the equation of L can be found.
參考: myself
2008-06-17 6:01 am
y-intercept is 4 means the straight line passes through ( 0, 4 )
sub. x=0 and y=4 into the line, we get
(2k^2 - 7k +3)0 +(9-k^2)4+3k^2 =0
k^2 -36= 0
k=6 or k= -6
sub the values of k into L, we get
L: 11x-9y+36=0
or 39x-9y+36=0
sub. x=0 and y=4 into the line, we get
(2k^2 - 7k +3)0 +(9-k^2)4+3k^2 =0
k^2 -36= 0
k=6 or k= -6
sub the values of k into L, we get
L: 11x-9y+36=0
or 39x-9y+36=0
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