Divide using synthetic division $$ ( x^{3}+2x^{2}+9x+18 ) \div ( -2x ) $$
Answer
The synthetic division table is:
$$ \begin{array}{c|rrrr}0&1&2&9&18\\& & 0& 0& \color{black}{0} \\ \hline &\color{blue}{1}&\color{blue}{2}&\color{blue}{9}&\color{orangered}{18} \end{array} $$The solution is:
$$ \frac{ x^{3}+2x^{2}+9x+18 }{ x } = \color{blue}{x^{2}+2x+9} ~+~ \frac{ \color{red}{ 18 } }{ x } $$Explanation
Step 1 : Write down the coefficients of the dividend into division table.Put the zero at the left.
$$ \begin{array}{c|rrrr}\color{blue}{0}&1&2&9&18\\& & & & \\ \hline &&&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrrr}0&\color{orangered}{ 1 }&2&9&18\\& & & & \\ \hline &\color{orangered}{1}&&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 0 } \cdot \color{blue}{ 1 } = \color{blue}{ 0 } $.
$$ \begin{array}{c|rrrr}\color{blue}{0}&1&2&9&18\\& & \color{blue}{0} & & \\ \hline &\color{blue}{1}&&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ 2 } + \color{orangered}{ 0 } = \color{orangered}{ 2 } $
$$ \begin{array}{c|rrrr}0&1&\color{orangered}{ 2 }&9&18\\& & \color{orangered}{0} & & \\ \hline &1&\color{orangered}{2}&& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 0 } \cdot \color{blue}{ 2 } = \color{blue}{ 0 } $.
$$ \begin{array}{c|rrrr}\color{blue}{0}&1&2&9&18\\& & 0& \color{blue}{0} & \\ \hline &1&\color{blue}{2}&& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ 9 } + \color{orangered}{ 0 } = \color{orangered}{ 9 } $
$$ \begin{array}{c|rrrr}0&1&2&\color{orangered}{ 9 }&18\\& & 0& \color{orangered}{0} & \\ \hline &1&2&\color{orangered}{9}& \end{array} $$Step 6 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 0 } \cdot \color{blue}{ 9 } = \color{blue}{ 0 } $.
$$ \begin{array}{c|rrrr}\color{blue}{0}&1&2&9&18\\& & 0& 0& \color{blue}{0} \\ \hline &1&2&\color{blue}{9}& \end{array} $$Step 7 : Add down last column: $ \color{orangered}{ 18 } + \color{orangered}{ 0 } = \color{orangered}{ 18 } $
$$ \begin{array}{c|rrrr}0&1&2&9&\color{orangered}{ 18 }\\& & 0& 0& \color{orangered}{0} \\ \hline &\color{blue}{1}&\color{blue}{2}&\color{blue}{9}&\color{orangered}{18} \end{array} $$Bottom line represents the quotient $ \color{blue}{ x^{2}+2x+9 } $ with a remainder of $ \color{red}{ 18 } $.