Anyone know this im stuck?

Which of the following is the explicit rule for a geometric sequence defined a recursive formula of a -5a for which the first term is 23?

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Annabelle's homework is 75% it took her three hours how long should she estimate it will take her to complete her homework.