ExamBro
ExamBro
MHT CET · Maths · Circle

The equation of a circle, which passes through the centre of the circle \(x^2+y^2+8 x+10 y-7=0\) and is concentric with the circle. \(2 x^2+2 y^2-8 x-12 y-9=0\), is

  1. A \(x^2+y^2-4 x+6 y-87=0\)
  2. B \(x^2+y^2+4 x+6 y-87=0\)
  3. C \(x^2+y^2+4 x+6 y+87=0\)
  4. D \(x^2+y^2-4 x-6 y-87=0\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(x^2+y^2-4 x-6 y-87=0\)

Step-by-step Solution

Detailed explanation

The required circle is concentric with the circle
\(
2 x^2+2 y^2-8 x-12 y-9=0
\)
i.e, centre is at \((2,3)\) and passes through the centre of the circle
\(
x^2+y^2+8 x+10 y-7=0
\)
i.e., through \((-4,-5)\)
Hence, the required equation is
\(
\begin{aligned}
& (x-2)^2+(y-3)^2=(2+4)^2+(3+5)^2 \\
& \Rightarrow x^2+y^2-4 x-6 y-87=0
\end{aligned}
\)