Try looking at this, it might help you. http://virtualnerd.com/algebra-1/relations-functions/relations/definitions/solution-set-definition (not made by me)
For instance if you have 85 dollars in debt and you want to pay it off monthly 15 dollars at a time, and you wan't to find how many months will it take to pay it off.
Hope it helps!
Combine like terms.
12x^4 + 4x^3 - x^2
P(x) = R(x) - C(x) Breaking even is the point where revenue starts to overtake cost. It is, therefore, the point where P(x) = 0. Since these are all linear functions, you know that after that point the business is profitable. P(x) = 0R(x) - C(x) = 015000x - (9000x+72000) = 015000x - 9000x - 72000 = 06000x - 72000 = 06000x = 72000x = 72000/6000x = 12 At 12 units the business breaks even.
