Simplify each expression.

1.) 4.2x + 8.1x + 1.8x - 2.1x

2.) x + 2 (x - y)

3.) (5x + y) - (4x - 9)

4.) 33.7y + 8.4 - 2.04y

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