PLEASE HELP ME!! 10 POINTS!

Perform the required operations on the following functions given: f(x)= 3-x; g(x)= -2x find g[f(x)]

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

Can any one me with the answers to these questions asap?