The synthetic division table is:
$$ \begin{array}{c|rrr}3&6&0&-60\\& & 18& \color{black}{54} \\ \hline &\color{blue}{6}&\color{blue}{18}&\color{orangered}{-6} \end{array} $$The solution is:
$$ \frac{ 6x^{2}-60 }{ x-3 } = \color{blue}{6x+18} \color{red}{~-~} \frac{ \color{red}{ 6 } }{ x-3 } $$Step 1 : Write down the coefficients of the dividend into division table. Put the zero from $ x -3 = 0 $ ( $ x = \color{blue}{ 3 } $ ) at the left.
$$ \begin{array}{c|rrr}\color{blue}{3}&6&0&-60\\& & & \\ \hline &&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrr}3&\color{orangered}{ 6 }&0&-60\\& & & \\ \hline &\color{orangered}{6}&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 3 } \cdot \color{blue}{ 6 } = \color{blue}{ 18 } $.
$$ \begin{array}{c|rrr}\color{blue}{3}&6&0&-60\\& & \color{blue}{18} & \\ \hline &\color{blue}{6}&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ 0 } + \color{orangered}{ 18 } = \color{orangered}{ 18 } $
$$ \begin{array}{c|rrr}3&6&\color{orangered}{ 0 }&-60\\& & \color{orangered}{18} & \\ \hline &6&\color{orangered}{18}& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 3 } \cdot \color{blue}{ 18 } = \color{blue}{ 54 } $.
$$ \begin{array}{c|rrr}\color{blue}{3}&6&0&-60\\& & 18& \color{blue}{54} \\ \hline &6&\color{blue}{18}& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ -60 } + \color{orangered}{ 54 } = \color{orangered}{ -6 } $
$$ \begin{array}{c|rrr}3&6&0&\color{orangered}{ -60 }\\& & 18& \color{orangered}{54} \\ \hline &\color{blue}{6}&\color{blue}{18}&\color{orangered}{-6} \end{array} $$Bottom line represents the quotient $ \color{blue}{ 6x+18 } $ with a remainder of $ \color{red}{ -6 } $.