Question
Question: If the circle x<sup>2</sup> + y<sup>2</sup> + 6x – 2y + k = 0 bisects the circumference of the circl...
If the circle x2 + y2 + 6x – 2y + k = 0 bisects the circumference of the circle x2 + y2 + 2x – 6y –15 = 0, then k is equal to
A
21
B
–21
C
23
D
–23
Answer
–23
Explanation
Solution
If the circle x2 + y2 + 6x –2y + k = 0 bisects the circumference of the circle x2 + y2 + 2x –6y –15 = 0 then their common chord passing through centre of second circle.