A truck rental company purchased a used truck for $18,000. It plans to rent a truck for $75 a day. Which equation would describe how the profit, y, on the truck is related to the number of days, x, that the truck earns income?

a. y=75*+18000

b. y=75x

c. 18000-75x

d. 75x-18000

Step-by-step explanation:

So two things happen, money is spent to buy the truck and then money is gotten by renting it out. So you already lost money at first. Then each day of renting you get 75 back.

Let's look at the first few days. Day 0 you are at - 18,000. Day 1 or renting you are at - 18000+75 and then day 2 is - 18000+75*2 = - 18000+150, and so on. So each day adds another + 75. So you can write it as - 18000+75x, where each x makes it go up by 75. Also, you can rearrange it so it's 75x-18000, which is the answer.