Answer :
F(x) stands for a function, and if x stands for the number of days, than she can do 225 per day, which would be the multiplication to find the toatl 225x.
Then, with 45 extra, we add that to the equation:
F(x) = 225x + 45
Answer: F(x) = 225x + 45
Credit to: @2Educ8
+ = <3