6

Set 11: Linear Inequalities (Intermediate)

Explanation

Answer: A

A region is defined by x+y6x + y \leq 6, x2x \geq 2, y1y \geq 1. What is the shape of this region?

A.

Triangle

✓ Correct
B.

Square

C.

Trapezoid

D.

Unbounded

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Find the vertices. 1. Intersection 1 (x=2,y=1x=2, y=1): (2,1)(2, 1) (Valid: 2+162 +1 \leq 6) 2. Intersection 2 (x=2,x+y=6x=2, x+y=6): 2+y=6y=42 +y=6 \rightarrow y=4. Vertex (2,4)(2, 4). 3. Intersection 3 (y=1,x+y=6y=1, x+y=6): x+1=6x=5x+1=6 \rightarrow x=5. Vertex (5,1)(5, 1). 4. Shape: Three vertices (2,1),(2,4),(5,1)(2,1), (2,4), (5,1) form a right triangle. Strategic Tip: Sketch the lines to visualize the enclosed region. Choice B is incorrect because it has 3 sides, not 4. Choice C is incorrect because it has 3 sides. Choice D is incorrect because the region is enclosed by the three lines.

Key Steps:

The correct answer is Triangle

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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