A concert promoter charges $65 per ticket for a concert. The promoter's cost will be $5500 plus $4 per ticket. If r = revenue and n = number of tickets sold, then r(n) shows how revenue (amount of money received from ticket sales) depends on the number of tickets sold.

r(n) = 65n

If c = cost and n = number of tickets sold, then c(n) shows how cost (expenses of the concert promoter) depends on the number of tickets sold.

c(n) = 4n + 5500

here you go mate

you would just plug in the formulas given to you following the hint it's:

r(n) - c(n)

which goes to

65n - (4n + 5500)

then we can simplify that to  

61n - 5500

Part 2:

61(850) - 5500

51850 - 5500 = 46350

this means if he sells 850 tickets he will make a net of 46350 dollars

150.6

all i did was i multiplied 5.02 by 30

-3.5 degrees per hour

step-by-step explanation:

find the unit rate:

-12   1/4 degrees           12.25 degrees

= - = -3.5 degrees per hour

      3   1/2 hours               3.5 hours