Find the constant, k, for plutonium-239 given that it’s half-life is 24,390 years.

Colby and jaquan are growing bacteria in an experiment in a laboratory. colby starts with 50 bacteria in his culture and the number of bacteria doubles every 2 hours. jaquan starts with 80 of a different type of bacteria that doubles every 3 hours. let x equal number of days. colbys experiment follows the model: a.) y=50*2^x b.) y=50*2^8x c.) y=50*2^12x jaquans experiment follows the model: a.)80*2^x b.)80*2^8x c.)80*2^12x

Need on this geometry question. explain how you did it.

Cot(90° − x) = 1 the value of x that satisfies this equation is °. a. 60 b. 135 c. 225 d. 315