Answer:
The equation of the parabola is 
.  The average rate of change of the parabola is -4.
Step-by-step explanation:
We must remember that a parabola is represented by a quadratic function, which can be formed by knowing three different points. A quadratic function is standard form is represented by:

Where:
 - Independent variable, dimensionless.
 - Dependent variable, dimensionless.
, 
, 
 - Coefficients, dimensionless.
If we know that 
, 
 and 
 are part of the parabola, the following linear system of equations is formed:



This system can be solved both by algebraic means (substitution, elimination, equalization, determinant) and by numerical methods. The solution of the linear system is:
, 
, 
. 
The equation of the parabola is 
. 
Now, we calculate the average rate of change (
), dimensionless, between 
 and 
 by using the formula of secant line slope:










The average rate of change of the parabola is -4.