Let s⇒x2+y2−8x−2y+8=0 s′⇒x2+y2+6x+8y−24=0 s′′⇒x2+y2−2x+2y+2=0 Equation of radical axis, ‌s−s′′=0‌ and ‌s′−s′′=0 ‌3x+2y−3=0 . . . (i) and ‌‌4x+3y−13=0 x=−17 and y=27 Radical centre (a,b)=(−17,27) a=−17 and b=27 Then, a+b=−17+27=10