7

Set 8: Exponential Functions (Intermediate)

Explanation

Answer: A

The function g(x)=80(0.75)x10g(x) = 80(0.75)^x - 10 has a horizontal asymptote at:

A.

y=10y = -10

✓ Correct
B.

y=80y = 80

C.

y=0.75y = 0.75

D.

y=0y = 0

Detailed Explanation

Choice A is correct. Choice A is the correct answer. The asymptote comes from the vertical shift. 1. Form: g(x)=abx+kg(x) = ab^x + k where k=10k = -10. 2. As xx \to \infty: (0.75)x0(0.75)^x \to 0, so g(x)010=10g(x) \to 0 - 10 = -10. 3. Asymptote: y=10y = -10. Strategic Tip: The constant term added/subtracted determines the horizontal asymptote. Choice B is incorrect because 80 is the coefficient, not the asymptote. Choice C is incorrect because 0.75 is the base. Choice D is incorrect because this ignores the 10-10 shift.

Key Steps:

The correct answer is y=10y = -10

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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