AP EAMCET Engineering 21 Sep 2020 Shift 2 Paper

(d) The radical axis of the co-axial system of circles with limiting points A(1,2) and B(−2,1) is the perpendicular bisector of line joining limiting points A and B.
∵ Mid-point of A and B is (−‌

1

2

,‌

3

2

) and slope of perpendicular to AB is −3
∴ Equation of required radical axis is y−‌

3

2

=−3(x+‌

1

2

)
⇒‌‌y−‌

3

2

=−3x−‌

3

2

⇒‌‌3x+y=0