9. -7/12
10. -2.75
11. 1.844
12. 4.539
The question is asking you to come up with a real-life example of something that can be represented as 15+ c= 17.50. If I were you I would do sales tax. You bought an item with a 15 dollar price tag, but when you go to check out 2.50 are added in tax to equal 17.50. to solve subtract 15 from 17.50: c= 2.50. Your variable (c) represents the sales tax. Hope that helps! :)
Yvette wants to earn a profit of $360, then. That means she has to make a total of $480. 480 divided by 18 is 26 and 2/3. That basically rounds up to $26.67.
480 = 18x
360 = 18x - 120
120(3) = 18x - 120
(I'm not that good at this, so don't take my word for it)
It would most likely take 3-4 hours, maybe even 5.