Picture Discription of how to get the slope of the secant line
To start of basically you have a secan line drawn, that means it touches two points on the graph. The first distance you have is the (x ) and the one next to it is the (h ). the vertical up to point a is f of x f(x) and then the distance up is f (x+h) because it has to go the disatnce of x and h. The cordinates of a is (x , f(x) ) and of b its ( (x+h) , f(x+h) ).
The math of how to get the difference quotient!
To find how those points and how its revelent, we have to use the slope formula. Since we are finding the slope we can find the slope to help find the difference qoutient. In the end we just cancel out things and we are left with our famous f(x+h)-f(x)/h!!!!!!!