The given equation represents the rate of expenditure in hundreds of dollars for a certain type of job:
[tex]E^{\prime}(x)=2x+7[/tex]
→ x represents the number of days since the start of the job
You have to determine the expenditure, E'(X), when the job takes three days (x=3), to do so replace the number of days into the equation and solve for E'(x)
[tex]\begin{gathered} E^{\prime}(x)=2x+7 \\ E^{\prime}(3)=2*3+7 \\ E^{\prime}(3)=6+7 \\ E^{\prime}(3)=13 \end{gathered}[/tex]
The total expenditure for a job that takes 3 days will be 13 hundred dollars.
