Question: Hey
i know how to convert the general formula into specific ones(ie.; a circle's specific formula x² + y² = r² can be derived from this, and then you draw you graph), but i have no idea how to go from a graph to the general formula (you know the HUUUGE one...)

Reb,

If all you have is a graph then you need to be able to tell enough from the graph to write an equation. You mentioned a circle, so if you have the graph of a circle and you can tell that the centre is at (2, -3) and the radius is 5 then you know that the equation is

(x - 2)² + (y + 3)² = 5²

Now expand and collect terms

(x - 2)² + (y + 3)² = 5²
x² - 4 x + 4 + y² + 6 y + 9 = 25
x² - 4 x + y² + 6 y - 12 = 0

The difficult step of course is looking at the graph and being able to determine the centre and the radius.

Penny