To identify which equations represent exponential decay, we look for equations in the form \( y = a \cdot b^x \) where \( 0 < b < 1 \) (indicating decay).
Let's evaluate the provided options:
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\( y = 0.25^x \):
- Here, \( b = 0.25 \) (which is less than 1). This represents exponential decay.
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\( y = 500(1/2)^x \):
- Here, \( b = \frac{1}{2} \) (which is less than 1). This represents exponential decay.
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\( y = 0.25x + 3 \):
- This is a linear equation, not an exponential function. It does not represent exponential decay.
-
\( y = 30(1.5)^x \):
- Here, \( b = 1.5 \) (which is greater than 1). This represents exponential growth, not decay.
Summary of Results:
The functions that represent exponential decay from the given options are:
- \( y = 0.25^x \)
- \( y = 500(1/2)^x \)