First you bring all the constant terms on the right hand side:
$$ \begin{cases}3x-8y+z-10=0 \\ 9x+8y-2z=-17 \\ 2z+9-4y=30
\end{cases} \iff \begin{cases}3x-8y+z=10 \\ 9x+8y-2z=-17 \\ -4y+2z=21
\end{cases}$$
Now you can write the matrix associated with the linear system, where the last column represents the constant terms:
$$\begin{pmatrix}
3&-8&1&10\\
9&8&-2&-17\\
0&-4&2&21
\end{pmatrix}$$
At this point you can solve the system.
First you bring all the constant terms on the right hand side: $$ \begin{cases}3x-8y+z-10=0 \\ 9x+8y-2z=-17 \\ 2z+9-4y=30 \end{cases} \iff \begin{cases}3x-8y+z=10 \\ 9x+8y-2z=-17 \\ -4y+2z=21 \end{cases}$$ Now you can write the matrix associated with the linear system, where the last column represents the constant terms: $$\begin{pmatrix} 3&-8&1&10\\ 9&8&-2&-17\\ 0&-4&2&21 \end{pmatrix}$$ At this point you can solve the system.