Which comparison is correct?

Apublic library wants to place 4 magazines and 9 books on each display shelf. the expression 4s+9s represents the total number of items that will be displayed on s shelves. simplify the expression

Which of the following pair(s) of circles have las a common external tangent? select all that apply. a and b a and c b and c

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?