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