Idon't get what i'm spose to put on it also how do you work this app i'm new

Jackie purchased 3 bottles of water and 2 cups of coffee for the family for $7.35. ryan bought 4 bottles of water and 1 cup of coffee for his family for 7.15. how much does each bottle of water cost? how much does each cup of coffee cost?

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

Find the solution set for this equation: t^2+7t=0 separate the two values with a comma.