The synthetic division table is:
$$ \begin{array}{c|rr}0&-3&-7\\& & \color{black}{0} \\ \hline &\color{blue}{-3}&\color{orangered}{-7} \end{array} $$The solution is:
$$ \frac{ -3x-7 }{ x } = \color{blue}{-3} \color{red}{~-~} \frac{ \color{red}{ 7 } }{ x } $$Step 1 : Write down the coefficients of the dividend into division table.Put the zero at the left.
$$ \begin{array}{c|rr}\color{blue}{0}&-3&-7\\& & \\ \hline && \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rr}0&\color{orangered}{ -3 }&-7\\& & \\ \hline &\color{orangered}{-3}& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 0 } \cdot \color{blue}{ \left( -3 \right) } = \color{blue}{ 0 } $.
$$ \begin{array}{c|rr}\color{blue}{0}&-3&-7\\& & \color{blue}{0} \\ \hline &\color{blue}{-3}& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ -7 } + \color{orangered}{ 0 } = \color{orangered}{ -7 } $
$$ \begin{array}{c|rr}0&-3&\color{orangered}{ -7 }\\& & \color{orangered}{0} \\ \hline &\color{blue}{-3}&\color{orangered}{-7} \end{array} $$Bottom line represents the quotient $ \color{blue}{ -3 } $ with a remainder of $ \color{red}{ -7 } $.