12.42×28.6 = estimate then find the pruduct

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

If a and −a are numbers on the number line, which expression must give the distance between them? a) 0 b) a c) |2a| d) |a|

Aprobability experiment is conducted in which the sample space of the experiment is s={7,8,9,10,11,12,13,14,15,16,17,18 }, event f={7,8,9,10,11,12}, and event g={11,12,13,14}. assume that each outcome is equally likely. list the outcomes in f or g. find p(f or g) by counting the number of outcomes in f or g. determine p(f or g) using the general addition rule.