AP EAMCET Engineering 18 Sep 2020 Shift 1 Paper

Equation of given circles
S1:x2+y2−4x−6y+5=0
S2:x2+y2−2x−4y−1=0
and ‌‌S3:x2+y2−6x−2y=0
∴ Radical axis of circles S1 and S2 is
2x+2y−6=0⇒x+y=3.....(i)
Similarly, the radical axis of circles S2 and S3 is
−4x+2y+1=0 ....(ii)
∵ Radical centre is point of concurrency of radical axes, from radical axes Eqs. (i) and (ii), we get
y=‌

11

6

and x=‌

7

6

∴ Radical centre is (‌

7

6

,‌

11

6

)