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