Big M Method 9F9B14
1. **State the problem:**
We want to minimize the objective function $$Z = 5x_1 + 3x_2$$ subject to the constraints:
$$2x_1 + 4x_2 \leq 12$$
$$2x_1 + 2x_2 = 10$$
$$5x_1 + 2x_2 \geq 10$$
$$x_1, x_2 \geq 0$$
2. **Introduce slack, surplus, and artificial variables:**
- For $$2x_1 + 4x_2 \leq 12$$, add slack variable $$s_1 \geq 0$$:
$$2x_1 + 4x_2 + s_1 = 12$$
- For $$2x_1 + 2x_2 = 10$$, add artificial variable $$a_1 \geq 0$$:
$$2x_1 + 2x_2 + a_1 = 10$$
- For $$5x_1 + 2x_2 \geq 10$$, subtract surplus variable $$s_2 \geq 0$$ and add artificial variable $$a_2 \geq 0$$:
$$5x_1 + 2x_2 - s_2 + a_2 = 10$$
3. **Formulate the Big-M objective function:**
We penalize artificial variables with a large positive number $$M$$ to ensure they are driven out of the solution:
$$Z = 5x_1 + 3x_2 + M a_1 + M a_2$$
4. **Set up the initial simplex tableau with variables $$x_1, x_2, s_1, s_2, a_1, a_2$$ and solve using simplex method:**
- The goal is to minimize $$Z$$ while satisfying all constraints.
- Artificial variables $$a_1$$ and $$a_2$$ must be removed from the basis for a feasible solution.
5. **Summary:**
- Use slack variable $$s_1$$ for the first inequality.
- Use artificial variable $$a_1$$ for the equality.
- Use surplus variable $$s_2$$ and artificial variable $$a_2$$ for the third inequality.
- Minimize $$Z = 5x_1 + 3x_2 + M a_1 + M a_2$$.
- Apply simplex iterations to find optimal $$x_1, x_2$$.
Since the problem requires the Big-M method setup, the final answer is the formulation above ready for simplex iterations.