Question

If the locus of the centre of the circle which cuts the circles $x^2+y^2+4x-6y+9=0$ and $x^2+y^2-4x+6y+4=0$ orthogonally is $ax+by+c=0$, then the ascending order of $a,b,c$ is

• A. a, b, c
• B. b, c, a
• C. c, a, b
• D. a, c, b

Answer 1

Answer: (B)

b, c, a

locus of the centre of the circle which cuts the circles $s_1$
and $s_2$ orthogonally is known as radical axis.
So, $e{q}^n$ of radical axis of given two circle is given by
$s_1-s_2=0$
$\Rightarrow 8x-12y+5=0$
$ax+by+c=0$
$a=8,b=-1,c=5$
acending order of a,b,c
b,c,a.