10.2 Ellipses

Ellipse is a set of all points (x,y) the sum of whose distances from weo fixed points is constant.

Note: Major Axis should always be the long axis.

There is another equation, which is eccentricity, it means the ovalness of an ellipse.
When the problem ask us to find a standard equation by giving us a equation, we should simplify first, and then complete the square form, remember to add the right number to both sides.