Jeff is designing the seating arrangement for a concert in his high school theater. To give everyone a good view, each row must have 4 more seats than the row before it, and the 1st row can only have 10 seats. Help Jeff plan the rest of the seating by solving for how many seats are in row 20. Then show Jeff how to create a general equation to predict the number of seats in any row. Show your work, and use complete sentences.