It is a type of conic section, a geometric shape that forms through the intersection ... (If a were zero, you would have a linear equation.) Through this equation, you can identify the vertex ...
The Theory of Equations: with an Introduction to the Theory of Binary Algebraic Forms. By W. S. Burnside A. W. Panton Fourth edition. 2 vols. Pp. xiv + 286 and xii + 292. (Dublin: Hodges ...