931 is what percent of 980

Given this information, which expression must represent the value of b?

In what form is the following linear equation written y=9x+2

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.