After finding the function, the domain of the function should be [0, ∞].
In the given question we have to find the what constraints are there on the domain of the function.
From the question, Fiona buys different amounts of gas at 2.25.
As we know that the set of input values that function take are the domain of the function.
The domain of the function is [0, ∞].
The given rate = 2.25
Let the gallons of gas is x.
So the amount of the gas in the form of function is
f(x) = Rate*x
f(x) = 2.25x
As the amount of gas can't be negative. So the domain of the function should be [0, ∞].
To learn more about function link is here
brainly.com/question/21145944
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