What is the slope of the line with equation y-3=-1/2(x-2)

Ahome improvement store rents it’s delivery truck for $19 for the first 75 minutes and $4.75 for each additional 1/4 hour. if a customer rented the truck at 11: 10 am and returned the truck at 1: 40 pm the same day, what would his rental cost be?

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)

Ineed to know the answer to this algebra question.