Using the following equation, find the center and radius of the circle. You must show and explain all work and calculations to receive credit. Be sure to leave your answer in exact form. x*2+ y*2+ 8x- 2y+ 15= 0

Initially 100 milligrams of a radioactive substance was present. after 6 hours the mass had decreased by 4%. if the rate of decay is proportional to the amount of the substance present at time t, find the amount remaining after 24 hours. (round your answer to one decimal place.)

Suppose the radius of a circle is 16. what issuppose the radius of a circle is 16. what is its circumference its circumference

Name the most appropriate metric unit for each measurement