1. Operational Research (OR)
The resolution of all OR problems go through four phases

2. First Phase
Identification of the problem and collection of all information and data

3. Second Phase Development of a mathematical model
write the objective function and the constraints
max f(x)
subject to:
g(x) = c equality constraints
h(x) < d inequality constraints
production cannot be negative

4. Analysis of the problem and solutions research
Third Phase
Analysis of the problem and solutions research

5. Fourth Phase
Check for solutions

6. (all of the data for the optimization model are known with certainty)
OR PROBLEMS
OPTIMIZATION
PROBLEM
LINEAR PROGRAMMING
...
Under Certainty
(all of the data for the optimization model are known with certainty)
Under Uncertainty
(all of the data for the optimization model are not known with certainty)

7. Optimization problems can be classified into two categories:
Problems with continuous variables (Kg, m, ...)
Problems with discrete variables (q1, q2, ...)