716x7 multiply with expanded form like 700 x 8 and + 80x8 can you guys help me?

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36

Which equation represents the function on the graph?

Derek purchased a new gym membership. it costs him seven dollars a month plus two dollars for every time that he visits the gym. he wants to spend less than 25 dollars a month to visit the gym. write an inequality that models the situation using the variable v for the number of visits per month. also find the maximum number of visits he can make to the gym and still keep his cost below 25 dollars a month.