Step 1: Plot constraints.
- \( 2x + y = 7 \): Intercepts (3.5, 0), (0, 7). Shade above.
- \( 2x + 3y = 15 \): Intercepts (7.5, 0), (0, 5). Shade above.
Feasible region vertices:
- Intersection: Solve \( 2x + y = 7 \), \( 2x + 3y = 15 \):
\[ y = 7 - 2x, 2x + 3(7 - 2x) = 15 \Rightarrow 2x + 21 - 6x = 15 \Rightarrow -4x = -6 \Rightarrow x = 1.5, y = 4. \] - With x-axis: \( 2x + 3y = 15 \), y=0: x=7.5.
- With y-axis: \( 2x + y = 7 \), x=0: y=7.
Vertices: (1.5, 4), (7.5, 0), (0, 7).
Step 2: Evaluate z:
- At (1.5, 4): z=8(1.5)+10(4)=12+40=52.
- At (7.5, 0): z=8(7.5)+10(0)=60.
- At (0, 7): z=8(0)+10(7)=70.
Minimum z=52 at (1.5, 4).
Answer: Minimum z=52 at x=1.5, y=4.
For the linear programming problem: \[ {Maximize} \quad Z = 2x_1 + 4x_2 + 4x_3 - 3x_4 \] subject to \[ \alpha x_1 + x_2 + x_3 = 4, \quad x_1 + \beta x_2 + x_4 = 8, \quad x_1, x_2, x_3, x_4 \geq 0, \] consider the following two statements:
S1: If \( \alpha = 2 \) and \( \beta = 1 \), then \( (x_1, x_2)^T \) forms an optimal basis.
S2: If \( \alpha = 1 \) and \( \beta = 4 \), then \( (x_3, x_2)^T \) forms an optimal basis. Then, which one of the following is correct?
Consider the following regions: \[ S_1 = \{(x_1, x_2) \in \mathbb{R}^2 : 2x_1 + x_2 \leq 4, \quad x_1 + 2x_2 \leq 5, \quad x_1, x_2 \geq 0\} \] \[ S_2 = \{(x_1, x_2) \in \mathbb{R}^2 : 2x_1 - x_2 \leq 5, \quad x_1 + 2x_2 \leq 5, \quad x_1, x_2 \geq 0\} \] Then, which of the following is/are TRUE?