I won't even bother with the first one...
We need to complete the square for both the x and y variables:
Now, . So looking at the first set of parenthesis we've got . Equating the linear coefficient of this expression and the one right above we see that , so . This means we want to add to to make it a perfect square since . But what we do to one side of the equation we need to do to the other. Thus:
Now to the y variable. The problem is identical and we find we need to add to both sides again:
So this circle has a center at and a radius of 1.