Hey,
So if you are working 8 hrs a day and $15 an hour multiply those together, that would give you $120 a day, and multiplying that by 5 days a week that would make $600 a week.
I did not even understand that equation
(x-5)(x+2)=0
roots: x=5 and x= -2
see attached photo for steps
Every 30 mins the water level goes up by 15 inches