# Forms of Equations Terminology

I have been studying different types of equations and have found differences in how the terms "Standard Form" and "General Form" are used. $$\\$$

For linear equations in two variables (line in the 2D Plane) the terminology I found was: $$\\$$ $$Ax + By = C \tag{Standard Form}$$ $$Ax + By + C =0 \tag{General Form}$$ $$\\$$

For linear equations in three variables (Plane in 3D space) the terminology was inverted: $$\\$$ $$Ax + By + Cz = D \tag{General Form}$$ $$Ax + By + Cz + D = 0 \tag{Standard Form}$$ $$\\$$ For Quadratic equations in one variable (Parabola in 2D Plane) I found that: $$\\$$ $$Ax^2 + Bx + C = 0$$

Is called by some authors as $$\textit{Standard Form}$$ and by others as the $$\textit{General Form}$$. $$\\$$

My doubt is:

What is the correct use of the terminology when an equation is equal to a constant, and when is equal to zero?

Thank you so much for any insight on the subject.

• I don't think there is any universally "correct" meaning of these terms. After all, they are equivalent equations. – John Doe Mar 24 at 23:25