[tex]\left\{\begin{array}{l}z=6+t\\z-2t+1=5\end{array}\right\; \; \left\{\begin{array}{l}z=6+t\\(6+t)-2t=4\end{array}\right\; \; \left\{\begin{array}{ccc}z=6+t\\6-t=4\end{array}\right\; \; \left\{\begin{array}{ccc}z=8\\t=2\end{array}\right\\\\\\Otvet:\; \; t=2\; ,\; z=8\; .[/tex]