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MHT CET · Maths · Circle

Two circles centered at \((2,3)\) and \((4,5)\) intersects each other. If their radii are equal, then the equation of the common chord is

  1. A \(x+y+1=0\)
  2. B \(x+y-1=0\)
  3. C \(x+y-7=0\)
  4. D \(x+y+7=0\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(x+y-7=0\)

Step-by-step Solution

Detailed explanation

Equation of common chord is \(S_1-S_2=0\), where \(S_1\) and \(S_2\) are equations of the circles
\(\therefore\left[(\mathrm{x}-2)^2+(\mathrm{y}-3)^2\right]-\left[(\mathrm{x}-4)^2+(\mathrm{y}-5)^2\right]\) \(=0 \)
\( \therefore-4 \mathrm{x}+4-6 \mathrm{y}+9+8 \mathrm{x}-16+10 \mathrm{y}-25=0 \)
\( \therefore 4 \mathrm{x}+4 \mathrm{y}-28=0 \quad \Rightarrow \mathrm{x}+\mathrm{y}=7 \)