1. The slope m of the line between the two points shown on the graph is 100 thousand subscriptions/year.
2. A sentence stating the meaning of the slope is: "Each year, 100,000 subscribers are added."
The slope describes the constant rate of change that explains the relationship between y and x.
The number of subscriptions in 2008 = 500,000
The number of subscriptions in 2010 = 700,000
The number of subscriptions in 2012 = 900,000
The slope = Rise/Run
= (y₂ - y₁)/(x₂ - x₁)
= (700 - 500)/(2010 - 2008)
= 100
Thus, the slope, m, of the graph is 100,000 subscribers.