Please explain so I know how to do it

What is the slope of the line shown below?

Aflute is on sale for 20% off. including the discount and 8% tax, the sales price is $216.

Boris needs to buy plastic spoons. brand a has a box 42 spoons for $2.37. brand b has a box of 72 spoons for $3.57. find the unit price for each brand. then state which brand is the better buy based on the unit price. round your answer to the nearest cent.