It cost $9 to go to pete's pottery place to make your own bowls for $3 per bowl. natalie goes to pete's pottery place and makes b bowls. she decides to make bowls 5 days this month so she can sell them at a craft fair.

part a: write an expression that will represent natalie's total cost for this month.

part b: if she makes 4 bowls each time she goes to pete's pottery place, what will her total cost be?