Hello juliakI'm not sure what type of equation you're looking for, since you've headed this post "Quadratics". But the simplest equation through two points will be a straight line, which will be of the form .

So, if we start there, and put in the two pairs of values:

When . So

When . So

So one possible equation is .

If you're looking for a quadratic equation - one of the form - there will be an infinite number passing through just two points, so you'll need more information if you're going to get a single answer.

Hope that helps.

Grandad