Answer:
W = 7x +3.
Step-by-step explanation:
Lizzie plans to volunteer 3 hours a week at an animal shelter in addition to her library work.
If she gives x hours per day in library work, then in a week she gives a total of 7x hours in library work.
Therefore, the total number of hours she works in a week (W) is given by
W = 7x +3.
So, this equation is the expression from the given example. (Answer)