(x−2a)(x−2b)+(y−2c)(y−2d)=0 x2−2(a+b)x+4ab+y2−2(c+d)y+4cd=0 x2+y2−2(a+b)x−2(c+d)y+4(ab+cd)=0 From general equation of circle, x2+y2+2gx+2fy+c=0 Center =(−g,−f) and radius =√(−g)2+(−f)2+C ∴ Here g=−(a+b) and f=−(c+d) Hence, center =(−g,−f)=((a+b),(c+d))