Final answer:
Sophia's total charge for tutoring as a function of hours tutored is represented by the equation y = 12 + 8.50x, where 12 is the base fee and 8.50 is the charge per hour.
Step-by-step explanation:
To represent Sophia's total charge for tutoring y as a function of the number of hours she tutors x, we need to account for both her hourly rate and her base fee. Sophia's hourly rate is $8.50 per hour, and she has a base fee of $12. For every hour she tutors, she earns an additional $8.50, and this is regardless of how many hours she tutors. Therefore, the equation to represent her total charge is:
y = 12 + 8.50x
This equation means that Sophia charges a one-time fee of $12 at the start of the tutoring session (when x = 0), which is the y-intercept. The slope is $8.50, indicating she charges $8.50 for each hour of tutoring. The correct function from the choices is therefore b) y = 12 + 8.50x.