Set 7: Exponential Functions

Explanation

Answer: B

Which statement describes the graph of $y = 5(0.8)^x$ ?

$Graph of y = 5(0.8)^x$

Starts at 5 and goes up.

Starts at 5 and goes down.

✓ Correct

Starts at 0.8 and goes up.

Starts at 0.8 and goes down.

Detailed Explanation

Choice B is correct. Choice B is the correct answer. Analyze $a$ and $b$ . 1. Initial: $a=5$ , so it starts at y=5. 2. Decay: $b=0.8 < 1$ , so it is decreasing (going down). Strategic Tip: Base $< 1$ means the graph slides down like a slide. Choice A is incorrect because it would need $b > 1$ . Choice C is incorrect because initial value is 5, not 0.8.

Key Steps:

•

The correct answer is Starts at 5 and goes down.

Why others are wrong:

A: Choice A 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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