Answer questions 15, 16, and 17. , explain all the steps to solve them extensively. if you don't have time to do all three, can you answer and explain questions 15 and 16? i really need with all of these and i don't understand what to do at all. you so much, i really appreciate it. i think my math teacher forgot to explain these types of problems for me before school was out, so i am completely clueless.

Runners run around the school's football field. the cross country coach determines that the width of the field is seventy yards shorter than the length. part a write an expression that represents the perimeter of the football field. let x represent the length of the football field. include parentheses in your expression. next, write an equivalent expression that does not include parentheses. what property or properties did you use to simplify? explain. part b the cross country coach later determines that the length of the football field is 120 yards. all students must run five laps. using your answer from part a, determine the actual number of yards that each athlete must run in the tryouts. in order to make the team, students must complete the laps in 6 minutes. how quickly must they run each lap?