What is the percent change of 36; 63

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

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