Work out the value of 3x + 5y
when x = -5 and y = 5

Suppose a pendulum is l meters long. the time, t,in seconds that it tales to swing back and forth once is given by t=2.01

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?