It tells me the answer but i need work, i don't get how to do it plzz and u it's case 5

Plz need answer now will mark which situations represent linear functions? check all that apply. a)the temperature rises and falls over the course of a day. temperature is a function of time. b)a baseball is hit into the outfield. the height of the ball is a function of time. c)a car goes 55 mph on the highway. distance is a function of time. d)a child grew 2 inches this year and 1 inch last year. height is a function of time. e)a movie director makes 2 movies per year. the number of movies is a function of the years.

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

It says factor each expression completely 8y+48