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