Write a linear equation in one variable to help you answer the question. Your friend Erin has a farm you are going to visit this weekend. You plan on knitting booties for each of her animals. You know that she has llamas (), which have 4 feet, and emus (), which have 2 feet. She also tells you that there are a total of 64 animal feet that could use your booties. Write an equation to represent the relationship between the number of each animal there are and how many total feet need booties.