Keith applies a new conditioner to his hair. He finds that the rate at which his hair grows can be modeled by a linear function. He observes that the rate of growth is 2 cm every 3 days. After 21 days, he measures the length of his hair to be 24
centimeters. What was the initial length of his hair?
Step-by-step explanation: His hair has grown 3cm 7 times over the course of 21 days. This totals 14 in of growth since 21/3*2=14. Then 24-14 gets you 20
