To find the correct exponential equation for the value of a car since its purchase, we can use the information provided from the points (0, 30000) and (1, 22500).
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Determine the initial value (at x=0): At \( x = 0 \), the value of the car is \( y = 30000 \). Therefore, the equation will have the form: \[ y = 30000 \cdot a^x \]
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Use the second point (1, 22500): At \( x = 1 \), the value of the car is \( y = 22500 \). Plugging this into the equation gives us: \[ 22500 = 30000 \cdot a^1 \]
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Solve for \( a \): \[ a = \frac{22500}{30000} = \frac{3}{4} \]
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Formulate the exponential equation: Now substituting \( a \) back into the original equation, we have: \[ y = 30000 \left(\frac{3}{4}\right)^x \]
This matches the fourth option given in the responses: \[ y = 30,000 \left(\frac{3}{4}\right)^x \]
Thus, the correct exponential equation representing the graph is: \[ \boxed{y = 30,000 \left(\frac{3}{4}\right)^x} \]