Answer:
The difference between Shelly's and Terrence's total points
Explanation:
The constant is 20. The constant is always on it's own. The variable is x and the coefficient is 90.
If the constant is negative (-), we are assuming that there is a difference. This difference is a comparison. Since Shelly has 90x points and Terrence has 90x - 20. Terrence has less points than Shelly. Terrence has 20 points less (from the expression) and therefore a difference. Since they using Shelly's points (90x) to calculate Terrence points (90x - 20). As you can see both expressions are similar and only the constant makes them unequal, therefore since the constant makes them unequal they are different.