Linear Programming: Simplex Method Algebraic Solution

Published on November 4, 2025

Linear-Algebra

Solve a maximization linear programming problem using the simplex method with algebraic steps. Find the optimal values for decision variables and the maximum objective function value.

Question

RESOURDRE par méthode algébrique en Français

Answer

The problem is a linear programming problem.
The objective function to maximize is:
Subject to the constraints:
We will solve this problem using the algebraic method (simplex method). First, we convert the inequalities into equalities by introducing slack variables and .
The problem becomes:
Maximize
Subject to:


We can write the objective function as .
Initial Simplex Tableau:
Step 1: Identify the entering variable.
The entering variable is the non-basic variable with the most negative coefficient in the Z-row. In this case, it is with a coefficient of -2. So, is the entering variable.
Step 2: Identify the leaving variable.
To find the leaving variable, we calculate the ratio of the RHS to the coefficients of the entering variable in each constraint row.
For :
For :
The smallest non-negative ratio is 1, which corresponds to the row. So, is the leaving variable. The pivot element is 3 (the coefficient of in the row).
Step 3: Perform pivot operations.
Make the pivot element 1 by dividing the row by 3.
New row (now row):
Now, make all other elements in the column zero.
  • For row: (where is the new row)
    :
    :
  • For Z row:
    :
    :
New Simplex Tableau:
Step 4: Check for optimality.
There is still a negative coefficient in the Z-row (-1/3 for ). So, the solution is not optimal. We repeat the process.
Step 1: Identify the entering variable.
The entering variable is (coefficient -1/3).
Step 2: Identify the leaving variable.
Calculate ratios:
For :
For :
The smallest non-negative ratio is , which corresponds to the row. So, is the leaving variable. The pivot element is .
Step 3: Perform pivot operations.
Make the pivot element 1 by multiplying the row by .
New row (now row):
Now, make all other elements in the column zero.
  • For row: (where is the new row)
    :
    :
    :
    :
  • For Z row:
    :
    :
    :
    :
    :
Final Simplex Tableau:
Step 4: Check for optimality.
All coefficients in the Z-row are non-negative. Therefore, the current solution is optimal.
The optimal values for the decision variables are:

The maximum value of the objective function is:
Let’s verify the solution with the original objective function:
.
And verify the constraints:
(satisfied)
(satisfied)
(satisfied)
The final answer is .