3. 与圆x2+y2=4x^{2}+y^{2}=4x2+y2=4及圆x2+y2−8x−6y+24=0x^{2}+y^{2}-8x-6y+24=0x2+y2−8x−6y+24=0都外切的圆的圆心在((( )))