Help with math hw D:

Where I would start is separate the y and x variables, so that they're on the opposite sides of the equal sign.

Or just recognize the general form of a circle... which I hope he knows, if he's going to graph one.

(x-h)^2 + (y-k)^2 = r^2
Equation of a circle centered at point (h,k) with radius r

As for the x>31/8 are you sure? None of the graph has any point >31/8.