How many eight letter combinations can be found in this way, visiting all the letters in the grid exactly once and assuming that all the letters in the grid are different

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

If you answer right ill give brainliest, : )

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