一題f4數學
2009-10-04 1:00 am
in the figure,two straight lines L1:-2x+5y=10 and L2 intersect at a point P on the y-axis.they also cut the x-axis at the points Q and R respectively.(a)find the coordinates of the points P and Q(b)if QR =9,find the equation of L2
回答 (1)
2009-10-04 2:02 am
✔ 最佳答案
Let P(0,y) Sub. into L1,y=2. So P(0,2)Sub. y=0 in L1, x=-5. So Q(-5,0) R(4,0)
Using two-point form, the equation of L2 is
(y-0)/(x-4)=(2-0)/(0-4)
-4y=2x-8
x+2y-4=0
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https://hk.answers.yahoo.com/question/index?qid=20091003000051KK01189