ExamBro
ExamBro
TS EAMCET · Maths · Circle

The equation of the radical axis of the pair of circles \(7 x^2+7 y^2-7 x+14 y+18=0\) and \(4 x^2+4 y^2-7 x+8 y+20=0\) is

  1. A \(x-2 y-5=0\)
  2. B \(2 x-y+5=0\)
  3. C \(21 x-68=0\)
  4. D \(23 x-68=0\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(21 x-68=0\)

Step-by-step Solution

Detailed explanation

Let \(S_1 \equiv x^2+y^2-x+2 y+\frac{18}{7}=0\) and \(S_2 \equiv x^2+y^2-\frac{7}{4} x+2 y+5=0\) Now, the radical axis of the pair of circles are \(S_1-S_2=0\) \(\Rightarrow \quad\left(x^2+y^2-x+2 y+\frac{18}{7}\right)\) \(-\left(x^2+y^2-\frac{7}{4} x+2 y+5\right)=0\)…