deletions | additions       diff --git a/untitled.tex b/untitled.tex  index f7a06aa..09b4a75 100644  --- a/untitled.tex  +++ b/untitled.tex 
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\begin{equation}  \left\{  \begin{eqnarray}  &x_{t+1}=x_{t}+a*t+6.9+E_{t}&\\  &z_{t}=x_{t}+N_{t}& \end{eqnarray}  \end{equation}  \begin{equation}