So only the expression for x should be specified in the answer? The worked examples give the answer in decimals, but I'm assuming the worked examples were done using a calculator.
I'm guessing you're using the Essentials Textbook right? It's a good textbook (probably the better one for methods anyways), but here is a case of a question that is a little bit redundant. They've left in that question to teach students how to use the change of base rule, but since you aren't given log tables anymore, the last bit is done on the calculator (even though it says not to..., because you'd need a log table that you don't have and don't need for the course anymore...). If anything, it's something that wasn't quite changed properly when CAS was introduced into the course.
Now, what you should take from this is to know how to use the change of base rule when you need to apply it, that's all you need to know for these types of questions.
=\frac{\log_{a}(N)}{\log_{a}(b)})
The whole decimals without a calculator seemed a bit odd to me when I first did that exercise a few years ago, but after realising what they were trying to do, it makes more sense (I didn't know about log tables and such during year 12, because you don't need to know about them

).
tl;dr, The question isn't great, just know how to use the change of base formula.