Step 1
The domain of a function refers to all the values that go into a function. The domain of a function is the set of inputs accepted by the function. The output values are called the range.
Step 2
From the domain in this question, the number of days the crew has worked will determine the length of the road in miles. The domain is the independent quantity in a function. The number of days the crew has worked is independent of the length of the road. It does not depend on it.
Hence, the answer is;
[tex]\begin{gathered} Domain-Number\text{ of days the crew has worked} \\ Range-Length\text{ of the road\lparen in miles\rparen} \end{gathered}[/tex]
Step 3
Choose the most appropriate set of values. The crew can work for at most 70 days. Therefore;
[tex]The\text{ domain will be all real numbers from 0 to 70}[/tex][tex]\begin{gathered} The\text{ range will be;} \\ L=3D+300 \\ L=3(70)\text{ + 300=210+300=510\lparen Maximum range value\rparen} \\ L=3(0)+300=300\text{ \lparen minimum range value\rparen} \end{gathered}[/tex]
The range will be;
[tex]The\text{ set of real all numbers from 300 to 510}[/tex]