four more than twice a number is greater than negative eighteen. Solve the inequality for the unknown number

Can someone explain to me how to do

Acyclist bike x distance at 10 miles per hour .and returns over the same path at 8 miles per hour.what is the cyclist average rate for the round trip in miles per hour ?

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction