Ataxi costs 1.65 for the first mile and 0.85 for each additional mile. which equation could be solved to find the number x of additional miles traveled in a taxi given that the total cost of three trip is $20?

1.65 + 0.85x= $20
           0.85x=$18.35
                 x=21 10/17 
first you write the equation 
then you have to subtract 1.65 from the equation but you also have to subtract it from 20 
then you divide 0.85 from 0.85x and from the 18.35 left over from subtracting 1.65 from 20 
then you should get x=21 10/17 (simplified) but the decimal form is a ongoing fraction so you can just round it up to the nearest hundredth