Question

8.
If the points (k,1), (2, -3) are conjugate w.r.t x^2 + y^2 + 4x - 6y - 12 = 0 then k =
a) - 3
b) 2/3
c) 5/4
d) 1​

Answer 1

Explanation:

Given points are conjugate

∴S12=0

x1x2+y1y2+2(x+x1)−3(y+y1)−12=0

2k−3+2(a+2)−3(1−3)−12=0

2k−3+2a+4+6−12=0

4k−5=0

k=5/4=1.25

[k]=[1.25]=1