Why is this question which seems to not involve Calculus or Linear Algebra not considered basic while idknuttin's questions which seem to involve Calculus or Linear Algebra are considered basic?
Because the first question is not completely obvious at first, one might try to do algebraic manipulations before figuring out that this doesn't work. The next step is then to use an algorithm to find an answer. Best practices for choosing and implementing this algorithm can be of interest. This isn't very advanced but it is good for a site such as this one to have information on these issues so visitors can learn. The other questions can simply be looked up, e.g. 1-3 is described on Wikipedia.
Note that the faq states:
Quantitative Finance Stack Exchange is a question and answer site for professionals and academics in quantitative finance
We expect a certain level of basic knowledge and that the everyone does a decent amount of research before asking a question.