[tex]$
\begin{array}{l}
5 + 0 = 5 \\
3 + 4 = 4 + 3 \\
(4 + 7) + 9 = 4 + (7 + 9) \\
8 \times 1 = 8
\end{array}
$[/tex]

None of these answers are correct.