Algebra 2, how do you solve these questions?

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?

Use the graph of the sine function y=2sinθ shown below

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10