Divide using synthetic division $$ ( x^{6}+4x^{5}-2x^{3}+7 ) \div ( x+1 ) $$
Answer
The synthetic division table is:
$$ \begin{array}{c|rrrrrrr}-1&1&4&0&-2&0&0&7\\& & -1& -3& 3& -1& 1& \color{black}{-1} \\ \hline &\color{blue}{1}&\color{blue}{3}&\color{blue}{-3}&\color{blue}{1}&\color{blue}{-1}&\color{blue}{1}&\color{orangered}{6} \end{array} $$The solution is:
$$ \frac{ x^{6}+4x^{5}-2x^{3}+7 }{ x+1 } = \color{blue}{x^{5}+3x^{4}-3x^{3}+x^{2}-x+1} ~+~ \frac{ \color{red}{ 6 } }{ x+1 } $$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.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & & & & & & \\ \hline &&&&&&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrrrrrr}-1&\color{orangered}{ 1 }&4&0&-2&0&0&7\\& & & & & & & \\ \hline &\color{orangered}{1}&&&&&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ 1 } = \color{blue}{ -1 } $.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & \color{blue}{-1} & & & & & \\ \hline &\color{blue}{1}&&&&&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ 4 } + \color{orangered}{ \left( -1 \right) } = \color{orangered}{ 3 } $
$$ \begin{array}{c|rrrrrrr}-1&1&\color{orangered}{ 4 }&0&-2&0&0&7\\& & \color{orangered}{-1} & & & & & \\ \hline &1&\color{orangered}{3}&&&&& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ 3 } = \color{blue}{ -3 } $.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & -1& \color{blue}{-3} & & & & \\ \hline &1&\color{blue}{3}&&&&& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ 0 } + \color{orangered}{ \left( -3 \right) } = \color{orangered}{ -3 } $
$$ \begin{array}{c|rrrrrrr}-1&1&4&\color{orangered}{ 0 }&-2&0&0&7\\& & -1& \color{orangered}{-3} & & & & \\ \hline &1&3&\color{orangered}{-3}&&&& \end{array} $$Step 6 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ \left( -3 \right) } = \color{blue}{ 3 } $.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & -1& -3& \color{blue}{3} & & & \\ \hline &1&3&\color{blue}{-3}&&&& \end{array} $$Step 7 : Add down last column: $ \color{orangered}{ -2 } + \color{orangered}{ 3 } = \color{orangered}{ 1 } $
$$ \begin{array}{c|rrrrrrr}-1&1&4&0&\color{orangered}{ -2 }&0&0&7\\& & -1& -3& \color{orangered}{3} & & & \\ \hline &1&3&-3&\color{orangered}{1}&&& \end{array} $$Step 8 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ 1 } = \color{blue}{ -1 } $.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & -1& -3& 3& \color{blue}{-1} & & \\ \hline &1&3&-3&\color{blue}{1}&&& \end{array} $$Step 9 : Add down last column: $ \color{orangered}{ 0 } + \color{orangered}{ \left( -1 \right) } = \color{orangered}{ -1 } $
$$ \begin{array}{c|rrrrrrr}-1&1&4&0&-2&\color{orangered}{ 0 }&0&7\\& & -1& -3& 3& \color{orangered}{-1} & & \\ \hline &1&3&-3&1&\color{orangered}{-1}&& \end{array} $$Step 10 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ \left( -1 \right) } = \color{blue}{ 1 } $.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & -1& -3& 3& -1& \color{blue}{1} & \\ \hline &1&3&-3&1&\color{blue}{-1}&& \end{array} $$Step 11 : Add down last column: $ \color{orangered}{ 0 } + \color{orangered}{ 1 } = \color{orangered}{ 1 } $
$$ \begin{array}{c|rrrrrrr}-1&1&4&0&-2&0&\color{orangered}{ 0 }&7\\& & -1& -3& 3& -1& \color{orangered}{1} & \\ \hline &1&3&-3&1&-1&\color{orangered}{1}& \end{array} $$Step 12 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -1 } \cdot \color{blue}{ 1 } = \color{blue}{ -1 } $.
$$ \begin{array}{c|rrrrrrr}\color{blue}{-1}&1&4&0&-2&0&0&7\\& & -1& -3& 3& -1& 1& \color{blue}{-1} \\ \hline &1&3&-3&1&-1&\color{blue}{1}& \end{array} $$Step 13 : Add down last column: $ \color{orangered}{ 7 } + \color{orangered}{ \left( -1 \right) } = \color{orangered}{ 6 } $
$$ \begin{array}{c|rrrrrrr}-1&1&4&0&-2&0&0&\color{orangered}{ 7 }\\& & -1& -3& 3& -1& 1& \color{orangered}{-1} \\ \hline &\color{blue}{1}&\color{blue}{3}&\color{blue}{-3}&\color{blue}{1}&\color{blue}{-1}&\color{blue}{1}&\color{orangered}{6} \end{array} $$Bottom line represents the quotient $ \color{blue}{ x^{5}+3x^{4}-3x^{3}+x^{2}-x+1 } $ with a remainder of $ \color{red}{ 6 } $.