the graph of liner function f passes through the point (1,-9) ad has a slope of -3 what is the zero of f

A box-and-whisker plot shows 5 number summary:                                   Class A                Class B1) minimum value      65                           562) 1st quartile            66                            793) median                  81                            914) 3rd quartile            89                            945) maximum value     95                          100
Interquartile range = 3rd Quartile - 1st Quartile Class A: 89 - 66 = 23Class B: 94 - 79 = 15
IQR indicates the spread of the of the scores over the median. Class A has a spread that his more than 50% of the scores of Class B.
Hope this helps!!  :)