Flora made 8 withdrawls of $65 each from her bank account. what was the overall change in her account

withdrawals are when cash is taken out from the account

Flora withdraws an amount of $75 at a time from her bank account

she makes 7 such withdrawals 

one withdrawal she takes out - $75

then seven withdrawals leads to - $75 x 7 = $525 

then overall change in her account has been a net withdrawal of $525

so the overall change in the account is -$525

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)