Absolute value is the distance between the number and 0. Since distance cannot be negative, the absolute value of something is always going to be positive. In this equation | x | = 12 since 12 is already a postive number and the distance between 12 and 0 is 12, this means that x is equal to 12.
if he starts at 0 then goes to 20 then add another 35 which gives you 55mph then he slows down you decrease 11 which is 44 then decrease again 7 gives you 37mph