A football team begins the season with 25 players. Each month they get 3 more players. Write an equation I represent the relationship between the numbers of months the football team has been playing, x, and the total number of players, y

You want to find y so it should start with y=

then the next piece that is unknown is the number of months, but you know there are 3 new ones each month so you know you have to have 3x so you have y=3x

and then you can't forget to keep the original 25 on the team so y=3x+25