What mathematical series doubles with every iteration?

What is the y-coordinate of the solution of the system of equations? [tex]y = 2x + 14 \\ - 4x - y = 4[/tex]y=

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.

Ametal rod needs to be 9 feet and 5.5 inches in length. the sections of the poles being used are each 1 foot and 10.5 inches long. how many 1ft 10.5in sections would be needed to complete the 9ft 5.5in metal rod? and how many inches of material will be left?