Please help I have a test tomorrow

I need explanation with D on both of these​

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

What are the domain and range of the function f(x)=2^x+1

Adeposit of 5500 at 6% for 3 years equals