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AP EAMCET · Maths · Pair of Lines

The equation of pair of straight lines parallel to \(X\)-axis and touching the circle \(x^2+y^2-6 x-4 y-12=0\)

  1. A \(y^2-4 y-21=0\)
  2. B \(y^2+4 y-21=0\)
  3. C \(y^2-4 y+21=0\)
  4. D \(y^2+4 y+21=0\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(y^2-4 y-21=0\)

Step-by-step Solution

Detailed explanation

Given circle is \(x^2+y^2-6 x-4 y-12=0\) \[ \begin{aligned} \text { Centre } & =(3,2) \\ \text { Radius } & =\sqrt{(3)^2+(2)^2+12}=\sqrt{9+4+12}=\sqrt{25} \\ r & =5 \end{aligned} \] Since, tangents are paralle to \(X\)-axis \(\therefore\) Let \(y=k\) be the tangent to the given…