[BlindMath] Average Rate of Change pr

[Susan Jolly]

These answers got me confused and I've studied a lot of calculus.  But 
remember this is pre-calculus.

First the average rate of change of a function over a certain interval is 
not the same as the average of the function itself over that same interval. 
Finding the average rate of change just requires a simple formula whereas 
find the average of the function is something more complex one will learn 
about in calculus.

Remember that the notation f(x) means a general formula for calculating y if 
you know x whereas f(x_1) or f(x_2) means the value of y at the specific 
points x_1 or x_2.

The formula for the average rate of change defined to be
a = [f(x_2) - f(x_1)]/(x_2 - x_1)

It would be nice to understand why this formula is correct but first you 
should memorize the formula and be able to use it.

In this  case the function is f(x) = x^2 - x + 4.

The value of this function when x = 2 is 6.
The value of this function when x = 6 is 34.
(Being able to plug numbers  into formulas and find the result is one of the 
things you are supposed to be comfortable with.)

so a = (34 - 6) / (6 - 2 ) = 28/4 = 7.

HTH,
Susan Jolly