Netflix made headlines in September 2011 when it split its streaming video service and its DVD by-mail service into two companies. This decision was based on projections that streaming videos will replace DVDs in the future.

Total DVD and Blu-ray disc sales in 2009 were $8.73 billion. For the purposes of this problem, you will combine DVD and Blue-ray disk sales into one category of DVD sales. A study by In-Stat predicted that "physical disc sales will decline by $4.6 billion by 2014," and that "streaming, on the other hand, should grow from its current $2.3 billion to $6.3 billion over the same time period (2009-2014)."¹²

What is the slope, including units, of the model for DVD sales?

Write an equation that represents the linear model for DVD sales. LetD= the sales of DVDs in billions of dollars, andt= the number of years after 2009.

Write an equation that represents the linear model for streaming videos. LetS= the total sales of streamed videos in billions of dollars, andt= the number of years after 2009.

In what year do the models predict streaming video sales to exceed DVD sales?