I have a question about "equivalence class" I don't know how to approach the question , proving that something is an equivalence relation is ok but i do not understand the equivalence class part.
my question is : 
*the first part was to prove only one of them is an equivalence relations and it was easy to show that R isnt because it is not symmetric
*but the second question was to show the equivalence classes and i don't even have the slightest idea on how to approach it.. i was told that it is {1,3,9},{2,6},{4},{5},{7},{8}, but i do not know how they got there
thank you all for any type of help , stay safe!
Hint: let $[\,x\,]$ denote the equivalence class of $x$, then $y\in[\,x\,]$ if and only if $y\,R\,x$.
Can you prove that, for example, $1\,R\,3$ and $1\,R\,9$ but $1\,\not R\,2$, $1\,\not R\,4$, etc.?