The concept of slope in the function  expresses the angle between the line and the positive direction of the  axis.
 represents the slope of the function β the rate of change of  relative to the rate of change of .
When two points on a certain line are known, the slope of the line can be calculated from them.Β 
If  is positive - the line rises
If  is negative - the line falls
If  the line is parallel to the  axis. (In a graph like this, where  the line coincides with the  axis.)
This calculation is done using the following formula:Β
where the two points and are on the mentioned line.Β
It is important to emphasize that the slope is constant for any line.Β
Note:
The greater the slope β the steeper the graph.
The smaller the slope β the more moderate β flatter the graph.
How will you remember this?
Remember that when the slope is equal to 0, the graph is parallel to the X-axis β it is very, very moderate β flat.
Therefore, as it increases, the graph will be steeper.