[tex]$1+2=3$[/tex]
I just installed a LaTeX in WordPress Plugin, and now have the ability to enter formulas inline in the blog.
[tex]$V~=~\left[ \begin{array}{ccc} V_{ud} & V_{us} & V_{ub} \\ V_{cd} & V_{cs} & V_{cb} \\ V_{td} & V_{ts} & V_{tb} \end{array} \right]$[/tex]