Answer:
The y-intercept indicates that the phone card started with 850 minutes. The slope indicates that 50 minutes were used per day.
Explanation:
The graph cuts the y-axis at 850.This indicates that the phone card started with 850 minutes before it was used.
The slope of the graph is -50.This means that in every increase of one in the input variable (number of days), you get a decrease of 50 in the output variable (number of minutes remaining). This indicates every day, 50 minutes were used, hence 50 minutes reduced from the card per day.