To model the relationship between the number of months (x) and the total amount of money Oliwia will have in her account (y), we start by recognizing that she initially deposits $3,000.
She earns $3 in interest per month, which means that after \( x \) months, she will earn \( 3x \) dollars in interest.
Therefore, the total amount of money in her account after \( x \) months can be expressed as:
\[ y = 3000 + 3x \]
This equation can be rearranged to match the standard linear function format:
\[ y = 3x + 3000 \]
Thus, the correct equation of a linear function that models this situation is:
\[ y = 3x + 3000 \]
The correct answer is \( y = 3x + 3,000 \), where \( x \) is the number of months and \( y \) is the total amount of money Oliwia will have in her account.