SOLUTION: Hi, I need help with this one. It's driving me crazy! A textbook company uses the equations R = 30x and C = 5x + 3000 to represent the revenue and cost of textbook sales respec

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Question 19292: Hi, I need help with this one. It's driving me crazy!
A textbook company uses the equations R = 30x and C = 5x + 3000 to represent the revenue and cost of textbook sales respectively. The number of textbooks is represented by x.
a) For what number of textbooks is the cost equal to the revenue?
b) Using the Profit Formula (Profit = Revenue - Cost), write an algabraic expression the represents the Profit for x textbooks.
Thanks for your help!
Answer by Earlsdon(6294) (Show Source):
You can put this solution on YOUR website!
a) To find the value of x which makes R = C, just set R = C and solve for x.
Simplify and solve for x. Subtract 5x from each side.
Divide both sides by 25.

Cost = Revenue for 120 books.
b)

Simplify.