b. 'x' stands for the number of times the cup is refilled.
c. 3 + 1.5 (5)= $10.50
d. My answer to part (c) makes sense because the price of the cup is $3, and I have to pay $1.50 for each additional refill, in accordance to the formula I wrote.
Step-by-step explanation:
The original price of the cup is 3 dollars, but with each refill you get, you have to pay $1.50.
