The explicit formula for a pyramid sequence is p(n) = n(n+1)(2n+1)/6

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

On saturday a souvenir shop had 125 customers.sixty four percent of the costumers paid with a credit card. how many costumers paid with cash?

In need of in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.