Explanation:
Slope, at its core, can be very simple both graphically or mathematically.
Mathematically:
Lets say we have a random straight line that goes through the points (2, 5), (6, 15), (4, 10), and (20, 50).
Take any two points on that line.
I will use (2, 5) and (4, 10) for the sake of simplicity.
The slope formula is
where point 1 is (x2,y2), and point 2 is (x1, y1).
Thus, the slope is (4-2)/(10-5), or 2/5