Can someone explain this to me. am i supposed to input the x=4 into each X spot or what???

How do i do this? i don’t understand

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.

Use circumcenter theorem to solve for the given values