This means that when linear equation and curve equation are combined to find a common solution, there are two different solutions.

y=ax+b

y=cx^2+dx+e

This is equivalent to the rotation and translation of the straight line y=ax+b coincides with the X axis, and the curve Y = CX 2+DX+E rotates and translates together. The converted curve has two intersections with the X axis [the new curve equation has two different roots].

Geometric meaning:

There are three positional relationships between a straight line and an ellipse (including a circle):

1, intersection-there are two intersections.

2. Tangency-Only one intersection point

3. Phase separation-no intersection