Wyatt has a $30 online gift card. he plans to buy as many books as he can. the cost of each book is $4. there is also a single shipping charge of $2. how many books can he buy without spending more than his gift card amount?

What are the first 4 terms in the multiplication pattern given by the formula 2×4n

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.

Check all that apply. f is a function. f is a one-to-one function. c is a function. c is a one-to-one function.