Which equation represents a line which is parallel to the line y=4x-3

Describe all the numbers that when rounded to the nearest thousand are 645,000

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

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15