$2.95 coat; 5% tax what is the answer i don't understand it

Which expression is equivalent to? assume x > 0 and y > 0.

Which undefined geometric term is described as a location on a coordinate plane that is designed by an ordered pair (x, y) ?

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