Question
Question: The equation of a family of lines is l (5x + 3y – 7) + m (3x + 10y + 4) = 0. The number of values o...
The equation of a family of lines is
l (5x + 3y – 7) + m (3x + 10y + 4) = 0. The number of values of k, for which the line kx + 5y + 9 = 0 will not belong to the given family-
A
1
B
Zero
C
3
D
Infinite
Answer
1
Explanation
Solution
Given family of lines passing through point of intersection of 5x + 3y – 7 = 0 and 3x + 10y + 4 = 0 i.e.
(2, –1).
Now kx + 5y + 9 = 0 will not belong family for which
k(2) – 5 + 9 ¹ 0
Ž k ¹ – 2, one value.