To solve this system of linear equations, we can use matrix operations. Specifically, we can represent the system as a matrix equation \(AX = B\) and then solve for \(X\) using the inverse of matrix \(A\) or other numerical methods.
Dado el sistema de ecuaciones:
\[
\begin{array}{l}
-2x - y - z + 5 = 0 \\
-x - 2y - z + 10 = 0 \\
-x - y - 2z + 8 = 0
\end{array}
\]
Podemos reescribirlo en forma matricial \(AX = B\), donde:
\[
A = \begin{bmatrix}
-2 & -1 & -1 \\
-1 & -2 & -1 \\
-1 & -1 & -2
\end{bmatrix}, \quad
B = \begin{bmatrix}
-5 \\
-10 \\
-8
\end{bmatrix}
\]
Al resolver el sistema, encontramos que:
\[
X = \begin{bmatrix}
-0.75 \\
4.25 \\
2.25
\end{bmatrix}
\]
Esto implica que:
\[
x = -0.75, \quad y = 4.25, \quad z = 2.25
\]
Los valores de las variables son:
\[
x = -\frac{3}{4}, \quad y = \frac{17}{4}, \quad z = \frac{9}{4}
\]
\[
\boxed{x = -\frac{3}{4}, \, y = \frac{17}{4}, \, z = \frac{9}{4}}
\]