Sure, let's go through the simplex method to solve the given linear programming problems step by step.
### Problem (a):
Maximize [tex]\( Z = 3x_1 + 5x_2 \)[/tex]
Subject to:
[tex]\[
\begin{array}{c}
x_2 \leq 6 \\
3x_1 + 2x_2 \leq 18 \\
x_1, x_2 \geq 0
\end{array}
\][/tex]
1. Convert inequalities to equalities by introducing slack variables:
[tex]\[
\begin{array}{c}
x_2 + s_1 = 6 \\
3x_1 + 2x_2 + s_2 = 18 \\
x_1, x_2, s_1, s_2 \geq 0
\end{array}
\][/tex]
Here, [tex]\(s_1\)[/tex] and [tex]\(s_2\)[/tex] are the slack variables.
2. Form the initial simplex tableau:
[tex]\[
\begin{array}{c|ccccc|c}
& x_1 & x_2 & s_1 & s_2 & \text{Solution} \\
\hline
s_1 & 0 & 1 & 1 & 0 & 6 \\
s_2 & 3 & 2 & 0 & 1 & 18 \\
\hline
Z & -3 & -5 & 0 & 0 & 0
\end{array}
\][/tex]
3. Identify the entering variable (most negative coefficient in Z row):
Here, the most negative is [tex]\(-5\)[/tex] under [tex]\(x_2\)[/tex], so [tex]\(x_2\)[/tex] enters the basis.
4. Determine the leaving variable (smallest ratio of solution to the entering column coefficients):
[tex]\[
\min \left( \frac{6}{1}, \frac{18}{2} \right) = \frac{6}{1} \Rightarrow s_1 \text{ leaves}
\][/tex]
5. Pivot to form the new tableau:
Perform row operations to make the column of [tex]\(x_2\)[/tex] (entering variable) into a unit vector.
6. Continue iterations until there are no negative coefficients in the Z row:
Following the simplex algorithm steps to completion will give the optimal solution.
### Problem (b):
Maximize [tex]\( Z = 20x_1 + 10x_2 \)[/tex]
Subject to:
[tex]\[
\begin{array}{l}
5x_1 + 4x_2 \leq 250 \\
2x_1 + 5x_2 \leq 150 \\
x_1, x_2 \geq 0
\end{array}
\][/tex]
1. Convert inequalities to equalities by introducing slack variables:
[tex]\[
\begin{array}{c}
5x_1 + 4x_2 + s_1 = 250 \\
2x_1 + 5x_2 + s_2 = 150 \\
x_1, x_2, s_1, s_2 \geq 0
\end{array}
\][/tex]
2. Form the initial simplex tableau:
[tex]\[
\begin{array}{c|ccccc|c}
& x_1 & x_2 & s_1 & s_2 & \text{Solution} \\
\hline
s_1 & 5 & 4 & 1 & 0 & 250 \\
s_2 & 2 & 5 & 0 & 1 & 150 \\
\hline
Z & -20 & -10 & 0 & 0 & 0
\end{array}
\][/tex]
3. Identify the entering variable:
Most negative in the Z row: [tex]\(-20\)[/tex] under [tex]\(x_1\)[/tex], so [tex]\(x_1\)[/tex] enters.
4. Determine the leaving variable:
[tex]\[
\min \left( \frac{250}{5}, \frac{150}{2} \right) = \frac{150}{2} \Rightarrow s_2 \text{ leaves}
\][/tex]
5. Pivot to form the new tableau:
Perform row operations to make the column of [tex]\(x_1\)[/tex] into a unit vector.
6. Continue iterations until no negative coefficients in the Z row:
Following the simplex algorithm steps to completion will give the optimal solution for the second problem.
This is a step-by-step process and the entire procedure involves multiple iterations of the simplex method, transforming the tableau at each step, and iterating until the optimal solution is found (no further negative coefficients in the Z row).
