Which of the following options is a valid technique when solving trigonometric functions? select all that apply.

algebraic properties of equality
factoring
zero product property
trigonometric inverse functions

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.