SOLUTION: The profit on a watch is given by P = X2 – 13 X – 80, where X is the number of watches sold per day. How many watches were sold on a day when there was a $50 loss?

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: The profit on a watch is given by P = X2 – 13 X – 80, where X is the number of watches sold per day. How many watches were sold on a day when there was a $50 loss?      Log On


   

Question 79075: The profit on a watch is given by P = X2 – 13 X – 80, where X is the number of watches sold per day. How many watches were sold on a day when there was a $50 loss?
Answer by 303795(602) About Me  (Show Source):
You can put this solution on YOUR website!
P=x%5E2-13x-80
A $50 loss is a profit of -$50.
-50=x%5E2-13x-80
0=x%5E2-13x-30
0=%28x-15%29%28x%2B2%29
ie x= 15 or x=-2
Selling -2 watches doesn't make sense so there were 15 watches sold.