Plz I need help on #12

Jackie purchased 3 bottles of water and 2 cups of coffee for a family for $7.35. brian 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? i need this done

Let f(x) = 1/x^2 (a) use the definition of the derivatve to find f'(x). (b) find the equation of the tangent line at x=2

Shane and abha earned a team badge that required their team to collect no less than 2000 cans for recycling. abha collected 178 more cans than shane did. write an inequality to determine the number of cans, s, that shane could have collected.