Devon babysits x hours a week after school for 5$ an hour, and also has a job as a cashier y hours a week for $10 an hour. he wants to earn atleast 70$. he can’t work any more than 10 hours a week because of school.

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle. he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field