ITP Cable requires a lower installation fee than Urban Cable. After six months with this company, you would have paid $1081 since the beginning of the year, and $1257 after 7 months of paying. how do i solve this in linear equation form

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236