The synthetic division table is:
$$ \begin{array}{c|rr}-18&8&-4\\& & \color{black}{-144} \\ \hline &\color{blue}{8}&\color{orangered}{-148} \end{array} $$The solution is:
$$ \frac{ 8x-4 }{ x+18 } = \color{blue}{8} \color{red}{~-~} \frac{ \color{red}{ 148 } }{ x+18 } $$Step 1 : Write down the coefficients of the dividend into division table. Put the zero from $ x + 18 = 0 $ ( $ x = \color{blue}{ -18 } $ ) at the left.
$$ \begin{array}{c|rr}\color{blue}{-18}&8&-4\\& & \\ \hline && \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rr}-18&\color{orangered}{ 8 }&-4\\& & \\ \hline &\color{orangered}{8}& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -18 } \cdot \color{blue}{ 8 } = \color{blue}{ -144 } $.
$$ \begin{array}{c|rr}\color{blue}{-18}&8&-4\\& & \color{blue}{-144} \\ \hline &\color{blue}{8}& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ -4 } + \color{orangered}{ \left( -144 \right) } = \color{orangered}{ -148 } $
$$ \begin{array}{c|rr}-18&8&\color{orangered}{ -4 }\\& & \color{orangered}{-144} \\ \hline &\color{blue}{8}&\color{orangered}{-148} \end{array} $$Bottom line represents the quotient $ \color{blue}{ 8 } $ with a remainder of $ \color{red}{ -148 } $.