Ineed with number 3-8 ! i have a math exam and also any tips or tricks to make this stick? ?

Rewrite the following without an exponent. (5/8)-1

Driving 75 mph, it takes alicia 2 hours to reach the airport to go on a vacation. it then takes her 4 hours to get to her destination with the jet traveling at a speed of 400 mph. how many miles does alicia travel to get to her destination?

8000 + 8800 + 8000 + 8 million + 80 trillion + another a katrillion equals