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AP EAMCET · Maths · Circle

If a direct common tangent drawn to the circles \(x^2+y^2\) \(6 x+4 y+9=0\) and \(x^2+y^2+2 x-2 y+1=0\) touches the circles at A and B , then \(\mathrm{AB}=\)

  1. A 9
  2. B 16
  3. C \(4 \sqrt{6}\)
  4. D \(2 \sqrt{6}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(2 \sqrt{6}\)

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \text { } x^2+y^2-6 x+4 y+9=0 \\ & \Rightarrow(x-3)^2+(y+4)^2=4 ...(i)\\ & \text { and } x^2+y^2+2 x-2 y+1=0 \\ & \Rightarrow(x+1)^2+(y-1)^2=1 ...(ii)\\ & C_1=(3,-4), C_2=(-1,1), r_1=2, r_2=1 \end{aligned}\) So,…