Set 4: Quadratic Equations (Advanced)

Explanation

Answer: A

Which function models a situation where revenue increases then decreases?

$R(x) = -2x^2 + 50x$

✓ Correct

$R(x) = 2x^2 + 50x$

$R(x) = 50x$

$R(x) = x^2$

Detailed Explanation

Choice A is correct. Choice A is the correct answer. 1. "Increases then decreases" describes a parabola opening downward (concave down). 2. This requires a negative leading coefficient ( $a < 0$ ). 3. Only Choice A has $a = -2$ . Choice B is incorrect because it opens upward (decreases then increases). Choice C is incorrect because it is linear. Choice D is incorrect because it opens upward.

Key Steps:

•

The correct answer is $R(x) = -2x^2 + 50x$

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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