Awoman bought some large frames for $15 each and some small ones for $7 each. she bought 20 frames for $172, how many of each size?

Trent wants to buy 2 packs of trading cards for 3 dollars each. the trading card packs that trent normally buys tend to come in packs of 6, 10, 12, or 15 cards. after selecting 2 packs, trent found that the first pack of cards cost 25 cents per card, and the second pack cost 30 cents per card. trent uses this information to write the equations below in order to compare c, the number of cards in each pack.

Can someone me out here and the tell me the greatest common factor

Rewrite so the subject can be y in the formula d=m-y/y+n