Solve the linear system LaTeX: \displaystyle \begin{cases} - 7 x + 2 y - 9 z = -35 \\ 2 x - 9 y - 4 z = 9 \\ 8 x + 4 y + 9 z = 16 \\ \end{cases}

The Solution is LaTeX: \displaystyle (-1, -3, 4) .