Do's and donts in handling measuring tools

Cynthia takes her dog to the park every 2 days. she bathes her dog every 7 days. if she took her dog to the park and bathed him today, how long will it be until she does both on the same day again?

Which expressions are equivalent to -6 + 3m

Julia is going for a walk through the neighborhood. what unit of measure is most appropriate to describe the distance she walks?