The half-life of the radioactive element unobtanium -41 is 20 seconds. If 48 grams of unobtanium-41 are initially present, how many grams are present after 20 seconds? 40 seconds? 60 seconds? 80 seconds? 100 seconds?

Which expression is equivalent to 2x^2+7x+4?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

Taylor wants to paint his rectangular deck that is 41 feet long and 24 feet wide. a gallon of paint covers about 350 square feet. how many gallons of paint will taylor need to cover the entire deck? round your answers to two decimal places when necessary.