With the questions and am i right on the 1st one?

Can someone me i’m confused. will give brainliest and a whole bunch of points

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

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.