Where is the centre of ? You don't need to calculate anything for this, just glimpse at the equation. Once you've found the co-ordinates of the centre (which took me roughly 0 seconds), substitute them into and show that you get . Then do the same for the other circle.

For 2, similarly, what are the coordinates of Q? So what are the coordinates of P and R? The coordinates of P and R are the centres of the larger circles. You know that the circles intersect at the points R and P (although not both), and from there you should be able to set up something to find the equations of the larger circles.

What have you been able to do?

Hint for 1)

Hint for 2)