What are the first five terms of the pattern with the formula 21n?
the first five terms are
, , , , and .

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?