How do i rearrange the equation eg=mgh to obtain an for a) m, b) g, c) h?

What's the difference between: x≥0 and nonnegative integer. ?

Question and answers are in the attached picture. you so much in advance.

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