ahemmm the domain for a x,y pair set is always the "x" value, or the 1st value in the pair, thus [tex]\bf \{(\boxed{3}, 5), (\boxed{8}, 6), (\boxed{2}, 1), (\boxed{8}, 6)\} \impliedby \textit{that's the \boxed{domain}}[/tex]
of course, the 8 is there twice, so, you don't need to put it twice, just once.
