Please Help me with this

What is the common difference in the following arithmetic sequence? 7,3,-1,-5

Amajor grocery store chain is trying to cut down on waste. currently, they get peaches from two different distributors, whole fruits and green grocer. out of a two large shipments, the manager randomly selects items from both suppliers and counts the number of items that are not sell-able due to bruising, disease or other problems. she then makes a confidence interval. is there a significant difference in the quality of the peaches between the two distributors? 95% ci for pw-pg: (0.064, 0.156)

For which pairs of functions is (f•g)(x)=12x? f(x)=3-4x and g(x)=16x-3 f(x)=6x2 and g(x)= 2/x f(x)= and g(x) = 144x f(x)=4x and g(x) =3x