What are the common factors of 6 and 18

Ataxi company charges $2.25 for the first mile and then $0.20 per mile for each additional mile, or f = $2.25 + $0.20(m - 1) where f is the fare and m is the number of miles. if juan's taxi fare was $6.05, how many miles did he travel in the taxi? if juan's taxi fare was 7.65, how many miles did he travel in taxi

Ineed to know the answer to this algebra question.

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.