Divide using synthetic division $$ ( x^{3}-3x^{2}+14 ) \div ( x+3 ) $$
Answer
The synthetic division table is:
$$ \begin{array}{c|rrrr}-3&1&-3&0&14\\& & -3& 18& \color{black}{-54} \\ \hline &\color{blue}{1}&\color{blue}{-6}&\color{blue}{18}&\color{orangered}{-40} \end{array} $$The solution is:
$$ \frac{ x^{3}-3x^{2}+14 }{ x+3 } = \color{blue}{x^{2}-6x+18} \color{red}{~-~} \frac{ \color{red}{ 40 } }{ x+3 } $$Explanation
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.
$$ \begin{array}{c|rrrr}\color{blue}{-3}&1&-3&0&14\\& & & & \\ \hline &&&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrrr}-3&\color{orangered}{ 1 }&-3&0&14\\& & & & \\ \hline &\color{orangered}{1}&&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -3 } \cdot \color{blue}{ 1 } = \color{blue}{ -3 } $.
$$ \begin{array}{c|rrrr}\color{blue}{-3}&1&-3&0&14\\& & \color{blue}{-3} & & \\ \hline &\color{blue}{1}&&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ -3 } + \color{orangered}{ \left( -3 \right) } = \color{orangered}{ -6 } $
$$ \begin{array}{c|rrrr}-3&1&\color{orangered}{ -3 }&0&14\\& & \color{orangered}{-3} & & \\ \hline &1&\color{orangered}{-6}&& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -3 } \cdot \color{blue}{ \left( -6 \right) } = \color{blue}{ 18 } $.
$$ \begin{array}{c|rrrr}\color{blue}{-3}&1&-3&0&14\\& & -3& \color{blue}{18} & \\ \hline &1&\color{blue}{-6}&& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ 0 } + \color{orangered}{ 18 } = \color{orangered}{ 18 } $
$$ \begin{array}{c|rrrr}-3&1&-3&\color{orangered}{ 0 }&14\\& & -3& \color{orangered}{18} & \\ \hline &1&-6&\color{orangered}{18}& \end{array} $$Step 6 : 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 } $.
$$ \begin{array}{c|rrrr}\color{blue}{-3}&1&-3&0&14\\& & -3& 18& \color{blue}{-54} \\ \hline &1&-6&\color{blue}{18}& \end{array} $$Step 7 : Add down last column: $ \color{orangered}{ 14 } + \color{orangered}{ \left( -54 \right) } = \color{orangered}{ -40 } $
$$ \begin{array}{c|rrrr}-3&1&-3&0&\color{orangered}{ 14 }\\& & -3& 18& \color{orangered}{-54} \\ \hline &\color{blue}{1}&\color{blue}{-6}&\color{blue}{18}&\color{orangered}{-40} \end{array} $$Bottom line represents the quotient $ \color{blue}{ x^{2}-6x+18 } $ with a remainder of $ \color{red}{ -40 } $.