Open to find question (mathematics)

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

What is the rate of change of a line that passes through (2,-5) and (6,-2)?

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?