What is the value of x to the nearest tenth? need

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

Math i have no idea how to do a and b

What is the solution for the following system of equations? use any method to solve. y = -x +4 y = x - 2 a. ( 4 , -2) b. (2, 1) c. (3, 1) d.(3, -2)