Trying to my son with foundations of algebra simplifying

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a.about 4 b.about 8 c.about 40 d.about 21

25 ! the line of best fit is h = 5a + 86. predict the height at age 16. show your work.

How can constraints be used to model a real-world situation?