PLEASE HELP QUICK I HAVE NO CLUE

Can someone me out here and the tell me the greatest common factor

Sandy is upgrading her internet service. fast internet charges $20 for installation and $52.45 per month. quick internet has free installation but charges $57.45 per month. part 1 out of 2 complete the equation that can be used to find the number of months after which the internet service would cost the same. use the variable x to represent the number of months of internet service purchased.

At the beginning of the year, adrian's savings account balance was \$28$28. each week, he deposits another \$15$15 into that account, and he doesn't spend any of his savings. is his savings account balance proportional to the number of weeks since the start of the year?