Question

Answer 15. C and 15.D

Answer 1

The -15 in the slope means that they are spending 15 dollars per day, since slope is rise over run, or in our case, dollars spent per day.  Dollars is y (rise), days is x (run).  The slope is negative since they are spending money every day.  Thus, the -15 is the amount of money they spend per day, and 150 is the amount they started with.  That's C.  For D., follow the x-axis to 7 and go across to the point on the y axis it coordinates with to find that after 7 days, one week, he has 45 left.