Divide using synthetic division $$ ( 2x^{2}+6x+8 ) \div ( x+1 ) $$
Answer
The synthetic division table is:
$$ \begin{array}{c|rrr}-1&2&6&8\\& & -2& \color{black}{-4} \\ \hline &\color{blue}{2}&\color{blue}{4}&\color{orangered}{4} \end{array} $$The solution is:
$$ \frac{ 2x^{2}+6x+8 }{ x+1 } = \color{blue}{2x+4} ~+~ \frac{ \color{red}{ 4 } }{ x+1 } $$Explanation
Step 1 : Write down the coefficients of the dividend into division table. Put the zero from $ x + 1 = 0 $ ( $ x = \color{blue}{ -1 } $ ) at the left.
$$ \begin{array}{c|rrr}\color{blue}{-1}&2&6&8\\& & & \\ \hline &&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrr}-1&\color{orangered}{ 2 }&6&8\\& & & \\ \hline &\color{orangered}{2}&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ 2 } = \color{blue}{ -2 } $.
$$ \begin{array}{c|rrr}\color{blue}{-1}&2&6&8\\& & \color{blue}{-2} & \\ \hline &\color{blue}{2}&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ 6 } + \color{orangered}{ \left( -2 \right) } = \color{orangered}{ 4 } $
$$ \begin{array}{c|rrr}-1&2&\color{orangered}{ 6 }&8\\& & \color{orangered}{-2} & \\ \hline &2&\color{orangered}{4}& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ 4 } = \color{blue}{ -4 } $.
$$ \begin{array}{c|rrr}\color{blue}{-1}&2&6&8\\& & -2& \color{blue}{-4} \\ \hline &2&\color{blue}{4}& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ 8 } + \color{orangered}{ \left( -4 \right) } = \color{orangered}{ 4 } $
$$ \begin{array}{c|rrr}-1&2&6&\color{orangered}{ 8 }\\& & -2& \color{orangered}{-4} \\ \hline &\color{blue}{2}&\color{blue}{4}&\color{orangered}{4} \end{array} $$Bottom line represents the quotient $ \color{blue}{ 2x+4 } $ with a remainder of $ \color{red}{ 4 } $.