Answer:
9
Step-by-step explanation:
I think what they are asking is to subtract the 3 tokens from 21 tokens he already has giving us 18. and since it says "Twice the number of tokens" I'm assuming you divide 2 from 18 giving you 9 tokens.
6 packs of 3
2 packs of 9
3 packs of 3, 1 pack of 9
answer: 3 ways
-x^2 + 7 is the simplified expression