Answer:
C(x) = x*(p + 2e + 3r)
Explanation:
Let's call the price of one pack of pencils as "p", the price of on pack of erase as "e" and the price of one roll of tape as "r".
The total packs of pencils: x
The total packs of erasers: 2x
The total rolls of tape: 3x
The total price of packs of pencils: xp
The total price of packs of erasers: 2xe
The total price of rolls of tape: 3xr
Let's call the total of money spent as C, so:
C(x) = xp + 2xe + 3xr
C(x) = x*(p + 2e + 3r)