1. The equations of 2 straight lines are given below:
l1: x/3-y/5 = 1
l4: y=px+q
If l1 and l4 are parallel to each other and the x-intercept of l4 is twice that of l1, find the values of p and q.
2. Find the equation of the straight line passing through point (-1,5) and with slope 2/3.
F4 maths
2010-01-01 3:12 am
回答 (2)
2010-01-01 3:28 am
✔ 最佳答案
1: x/3 - y/5 = 15x - 3y = 15
y = 5x/3 - 5
slope = 5/3
as l1 and l4 are parallel, (5/3)* p = -1, p = -3/5
for l4, when y = 0 , x = -q/p = 5q/3
for l1, when y = 0 , x = 3
so 2*3 = 5q/3 , q = 18/5
2: (y-5)/[x-(-1)] = 2/3
3(y-5) = 2(x+1)
3y-15 = 2x+2
equation : 3y-2x-17 = 0
2009-12-31 19:47:04 補充：
第一題樓下果位先O岩,
我E 個系perpendicular既計法, SOR.
2010-01-01 3:28 am
l1:5x-3y=15=>slope of l1=5/3 and so p=5/3
the ix-ntercept of l1 is 3 => x-intercept of l4 is 6
and so sub. x=6,y=0 into l4=>q=-10
2009-12-31 19:32:34 補充：
2 y-5=(2/3)(x+1) => 2x+2=3y-15 =>2x-3y+17=0
the ix-ntercept of l1 is 3 => x-intercept of l4 is 6
and so sub. x=6,y=0 into l4=>q=-10
2009-12-31 19:32:34 補充：
2 y-5=(2/3)(x+1) => 2x+2=3y-15 =>2x-3y+17=0
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