In mathematics, a linear equation is a type of equation. In a linear equation, both terms have to be constant. A linear equation is the equation of a straight line. This type of equation is written in the form:
y = mx + b
or (y - y1) = m(x - x1)
where : m = the rate of change, or slope.
The slope is how fast the line moves up or down. Larger numbers will make the slope steeper.
If m is a negative number, then the line will appear to fall or go down the page when read from left to right.
If m is a positive number, then the line will appear to climb the page when read from left to right.
While b = the y-intercept of the function.
This is where the function crosses the y - axis of the coordinate plane.The first equation is called slope-intercept form, because in it, the slope (m) and y-intercept (b) are easily found.The second equation is called point-slope form, because in it, a point on the graph (x1, y1) and the slope (m) are easily found.
Also, an easier way to know if a graph is positive or negative is to imagine the Y axis as the 12 o clock point in a clock so if the line is before 12 it is negative and if it is after 12 it is positive