The equation of a straight line or a linear equation can be written in several different forms.
The first and most common form of a linear function or line is 
.
is called the gradient of the line and 
is the y-intercept of the line.
Each gradient-intercept form can be translated into the general form.
The general form:
where 
, respectively.
Equations of lines that are not parallel to any coordinate axis and do not go through the coordinate origin can be written differently.
Let the line intersect the abscissa axis at the point A (a, 0) and the ordinate axis at the point B (0, b). If we know these two points, we can write the equation of the line in the intercept form.
respectively.
