Hi guys please explain I don’t really get it thanks if you help

Solve for x -2.3(r - 1.2 ) = -9.66 enter you answer as decimal.

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

What is the value of x when x + 7 = 21?