The title might not describe my question really. I want to ask that there are several questions like what have I done wrong or what is my mistake. I usually answer these question telling them their mistake but in some of those question I additionally give them the link for an alternative solution for a exactly same question usually of website "toppr" etc. So is this desirable behavior? Or should I change my behavior and instead post the solution using MathJax? I usually don't do so because the main question is about identification of mistake and not about alternative solution but to give them some help I do so. So should I change this behaviour or is it fine? Or should I stop posting alternative solutions only?
There is nothing wrong with that approach (as long as the question is acceptable, of course). As long is your answer contains the explanation about where the error is, it is fine to add links to external sites with information which the OP may find relevant to the question.