# Find the equation of a circle whose centre $(3,-1)$ and which cuts off a chord of length $6$ units on the line $2x-5y+18=0$.
$\begin{array}{1 1}(x-3)^2+(y+1)^2=38\\(x+3)^2+(y+1)^2=38\\(x-3)^2+(y+1)^2=28\\(x-3)^2+(y-1)^2=38\end{array}$