Final answer:
The equation of the line is y = 15x + 25 representing the cost of the library membership and additional charges for each book.
Step-by-step explanation:
To determine the equation of the line, we can use the slope-intercept form, which is given by y = mx + b, where m is the slope and b is the y-intercept.
Based on the information given, the y-intercept is $25 (a = 25) and the slope is 15 (b = 15). Therefore, the equation of the line would be y = 15x + 25.
In this equation, x represents the number of books to be issued and y represents the cost, including the membership fee and additional charges for each book. If you want to find the cost for a specific number of books, substitute that value for x in the equation and solve for y.