What is the slope of the line that passes through points (9,5) and (21,1)? write you answer in simplest form.

Pls urgent max amount of points will be given and pls do not answer if unsure or you will be reported by me and brainliest answer gets the brainliest .. thing so yeh

Two lines parallel to a third line are parallel to each other. always sometimes or never

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