Timothy has begun selling copies of his first work of art. In the first year, he sold 200 copies. In the second year, he sold 240 copies. In the sixth year, he sold 400 copies. Suppose that he continues to increase his sales at the same rate.

Write an equation that will help Timothy calculate how many copies of his work he can expect to sell on y^th year.

Instruction: Add or subtract like terms and then write your answer without any space(s) and begin your answer with N=. Write your answer in the format N=a+by