To determine the correct equation from the given options based on the provided points (-2, 1.28) and (1, 2.5), we can analyze the points in relation to the equations.
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Exponential Growth/Decay: The options provided suggest that the graph might be an exponential function of the form \( y = a \cdot b^x \), where \( a \) and \( b \) are constants.
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Checking the given points:
- For the point (-2, 1.28):
- Substitute \( x = -2 \) into the equations and check if \( y \) approximates to 1.28.
- For the point (1, 2.5):
- Substitute \( x = 1 \) into the equations and check if \( y \) approximates to 2.5.
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By testing each option with the points:
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For Option 1: \( y = 2 \cdot (-1.25)^x \)
- At \( x = -2 \): \( y = 2 \cdot (-1.25)^{-2} \) (Not applicable since we cannot take negative base to a power)
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For Option 2: \( y = 2 \cdot (1.25)^x \)
- At \( x = -2 \): \( y = 2 \cdot (1.25)^{-2} \approx 2 \cdot 0.64 \approx 1.28 \) (Valid)
- At \( x = 1 \): \( y = 2 \cdot (1.25)^1 = 2 \cdot 1.25 = 2.5 \) (Valid)
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For Option 3: \( y = 1.25 \cdot (2)^x \)
- At \( x = -2 \): \( y = 1.25 \cdot (2)^{-2} = 1.25 \cdot 0.25 = 0.3125 \) (Not valid)
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For Option 4: \( y = -2 \cdot (1.25)^x \)
- At \( x = -2 \): \( y = -2 \cdot (1.25)^{-2} < 0 \) (Not valid)
Based on the calculations, Option 2:
\( y = 2 \cdot (1.25)^x \)
is the only option that satisfies both points.
Therefore, the answer is: y = 2 \cdot (1.25)^x.