Circle: When x and y are both squared and the coefficients on them are the same — including the sign.
For example, take a look at 3x2 – 12x + 3y2 = 2. Notice that the x2 and y2 have the same coefficient (positive 3). That info is all you need to recognize that you’re working with a circle.
Parabola: When either x or y is squared — not both.
