Given equations of circle is x2+y2=16 and x2+y2+2x+2y=0 According to the questions, Length of the tangent from (h,k) to the circle x2+y2=16 =2× Length of the tangent from (h,k) to the circle x2+y2+2x+2y=0 ⇒ √h2+k2−16=2×√h2+k2+2h+2k On squaring both sides, we get h2+k2−16=4×(h2+k2+2h+2k) ⇒ 3h2+3k2+8h+8k+16=0