$\"\"$

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(a).

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The function $\"\"$ , where $\"\"$ represents the number of years and $\"\"$ is the present cost.

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Find $\"\"$ , when $\"\"$ and $\"\"$ .

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Consider $\"\"$ .

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Substitute the values $\"\"$ and $\"\"$ in $\"\"$ .

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$\"\"$

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Therefore, the price of an oil change for the car is $\"\"$ .

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$\"\"$

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(b)

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The rate of change is the first derivative of that function.

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Consider $\"\"$ .

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Apply derivative on each side with respect to $\"\"$ .

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$\"\"$

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Substitute $\"\"$ in the above equation.

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$\"\"$

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$

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(c)

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The rate of change of $\"\"$ is $\"\"$ .

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The function $\"\"$ .

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Consider $\"\"$ .

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$\"\"$

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Here the constant of proportianality is $\"\"$ .

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$\"\"$

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(a).

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The price of an oil change for the car is $\"\"$ .

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(b).

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$\"\"$ .

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$\"\"$

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(c).

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The constant of proportianality is $\"\"$ .