This problem came about because I was talking about solving the equation 4x + y = – 14 for y and there was a little confusion about how I could subtract 4x from – 14. Although this was really a problem with combining like terms, I figured that now was as good of a time as ever to reinforce the idea of combining like terms.
“Yaletta bought an unknown number of tomatoes at $4 each, but when she got home, she found out that all of the tomatoes were rotten. In addition, she checked her receipt and realized that the store had charged $14 to carry the tomatoes to the car. Write an equation to model Yaletta’s total losses.” (as a signed number)
- What does y represent?
- What does x represent?
- What does -4 mean?
- What does -14 mean?
- How much would Yaletta lose if she bought 25 tomatoes? (as a signed number)
What’s even more interesting about this problem for me is that later in the day I was talking about ratio and proportion and so I used this same problem to ask questions such as:
- Do you think that it’s fair that the $14 dollar charge is fair? Why or why not?
- Would it be more appropriate to have a charge proportional to the number of bags of tomatoes carried to the car?
- What additional information would we need to know in order to make this change to the charge?
