Me i’ve been stuck on this for a while

Fiona races bmx around a circular dirt course. if the radius of the course is 70 meters, what is the total distance fiona covers in two laps of the race? a. about 30,772 meters b. about 15,386 meters c. about 879.2 meters d. about 439.6 meters e. about 219.8 meters23 points hurry

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

Aline has a slope of and a y-intercept of –2. what is the x-intercept of the line?