9

Set 7: Linear Inequalities

Explanation

Answer: A

Maximize P=x+yP = x + y subject to yx+4y \leq -x + 4, yx+2y \leq x + 2, y0y \geq 0.

A.

44

✓ Correct
B.

33

C.

66

D.

22

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Find vertices and evaluate. 1. Intersection 1: y=x+4y = -x + 4 and y=x+2y = x + 2. x+2=x+42x=2x=1,y=3x + 2 = -x + 4 \rightarrow 2 x = 2 \rightarrow x = 1, y = 3. Vertex (1,3)(1, 3). 2. Intersection 2: y=x+4y = -x + 4 and y=0y = 0. x=4x = 4. Vertex (4,0)(4, 0). 3. Intersection 3: y=x+2y = x + 2 and y=0y = 0. x=2x = -2. Vertex (2,0)(-2, 0). 4. Evaluate P: - (1,3):1+3=4(1, 3): 1 + 3 = 4 - (4,0):4+0=4(4, 0): 4 + 0 = 4 - (2,0):2+0=2(-2, 0): -2 + 0 = -2 5. Max: 4 Strategic Tip: Sometimes multiple vertices give the same optimal value (multiple solutions). Choice B is incorrect. Choice C is incorrect. Choice D is incorrect.

Key Steps:

The correct answer is 44

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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