Question 308584
you can always start by graphing an inequality

{{{graph( 500, 500, -5, 5, -5, 5, 4(x-3)^2+9(y+1)^2<36 )}}}

The center is always determined by what is added to x and y: it is (3, -1). 

This is not a circle so I am not sure how to answer the question about radius.