Question
Question: If the circle x<sup>2</sup> + y<sup>2</sup> + 4x + 22y + c = 0 bisects the circumference of the circ...
If the circle x2 + y2 + 4x + 22y + c = 0 bisects the circumference of the circle x2 + y2–2x + 8y – d = 0 then
c + d =
A
40
B
50
C
60
D
70
Answer
50
Explanation
Solution
Common chord is diameter of
x2 + y2 – 2x + 8y – d = 0
̃ 6x + 14y + c + d = 0 passer through (1, – 4)
̃ 6 (1) + 14(–4) + c + d = 0 ̃ c +d = 50