A food scientist uses a mixture of the gases helium and argon to preserve packaged food. The amount of each gas the scientist uses for the mixture is modeled by the equation 5.6H + 0.56A = 22.4, where H and A
are the masses, in grams, of helium and argon, respectively. If the scientist uses 10 grams of argon, how
many grams of helium are used?
PLEASE HELP!

Juanita wade's new car has an msrp of $28,902.11 including title and processing fees. the premier package which includes surround sound and dvd player costs three times the amount of the in-style package which includes leather seats and select wheels. the total cost of her new car was $34,290.08 which included the 6.5% sales tax. find the cost of the premier package to the nearest cent.