I dont know how how to answer the question

What number produces an irrational number when multiplied by -1.25

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.

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter?