How would i find the measure of y for this problem?

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

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angles. measure need asap

Which of the following is the inverse of y = 3∧x y = 1/3∧x y = ㏒3x y = (1/3) ∧x y = ㏒ 1/3∧x