What is X plus seventeen equals three

How is working backward similar to solving an equation?

Can some one me with these questions

Olive's solar powered scooter travels at a rate of 30 miles per hour. what equation can she use to calculate her distance with relation to the time she traveled? h=hours m=miles 1. h=m+30 2. m=30h 3. m=h+30 4. h=30m