What is 1,424,000,000 in scientific notation

Don't know how to find x given these segment lengths

What is the x-intercept and y-intercept of the equation 2x+1. 2o

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance