X^2/a^2+y^2/b^2= 1

Multiply by a^2b^2 on both sides:

b^2x^2+a^2y^2=a^2b^2

The corresponding coefficient is constant:

Ax^2+By^2=C.

This equation is a general equation of ellipse, but it should be noted that:

A≠B, and A, B and C are all positive numbers.

Supplement: An ellipse is very similar to a circle. The difference is that the x and y radii of an ellipse are different, while the x and y radii of a circle are the same. In mathematics, an ellipse is the locus of a point on a plane, in which the sum of the distances between two fixed points is the same constant.