HELP PEASE ASAP 20 POINTS

What is 3x19x28/39x90x2/0

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.)

Describe a situation that you could represent with the inequality x< 17

Find the amplitude of a sinusoidal function that models this temperature variation