Circles are c1,x2+y2+2x+4y+1=0 c2,x2+y2−2x+6y−3=0 On comparing with general form of circles x2+y2+2gx+2fy+c=0 where, centre =(−g,−f) and radius =√g2+f2−c ∴ c1=(−1,−2) and r1=√1+4−1=2 c2=(1,−3) and r2=√1+9+3=√13 ∴ d=c1c2=√(−1−1)2+(−2+3)2=√4+1=√5