Divide using synthetic division $$ ( 3x^{3}-17x^{2}+28x-12 ) \div ( x-3 ) $$
Answer
The synthetic division table is:
$$ \begin{array}{c|rrrr}3&3&-17&28&-12\\& & 9& -24& \color{black}{12} \\ \hline &\color{blue}{3}&\color{blue}{-8}&\color{blue}{4}&\color{orangered}{0} \end{array} $$The solution is:
$$ \frac{ 3x^{3}-17x^{2}+28x-12 }{ x-3 } = \color{blue}{3x^{2}-8x+4} $$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.
$$ \begin{array}{c|rrrr}\color{blue}{3}&3&-17&28&-12\\& & & & \\ \hline &&&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrrr}3&\color{orangered}{ 3 }&-17&28&-12\\& & & & \\ \hline &\color{orangered}{3}&&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 3 } \cdot \color{blue}{ 3 } = \color{blue}{ 9 } $.
$$ \begin{array}{c|rrrr}\color{blue}{3}&3&-17&28&-12\\& & \color{blue}{9} & & \\ \hline &\color{blue}{3}&&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ -17 } + \color{orangered}{ 9 } = \color{orangered}{ -8 } $
$$ \begin{array}{c|rrrr}3&3&\color{orangered}{ -17 }&28&-12\\& & \color{orangered}{9} & & \\ \hline &3&\color{orangered}{-8}&& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 3 } \cdot \color{blue}{ \left( -8 \right) } = \color{blue}{ -24 } $.
$$ \begin{array}{c|rrrr}\color{blue}{3}&3&-17&28&-12\\& & 9& \color{blue}{-24} & \\ \hline &3&\color{blue}{-8}&& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ 28 } + \color{orangered}{ \left( -24 \right) } = \color{orangered}{ 4 } $
$$ \begin{array}{c|rrrr}3&3&-17&\color{orangered}{ 28 }&-12\\& & 9& \color{orangered}{-24} & \\ \hline &3&-8&\color{orangered}{4}& \end{array} $$Step 6 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 3 } \cdot \color{blue}{ 4 } = \color{blue}{ 12 } $.
$$ \begin{array}{c|rrrr}\color{blue}{3}&3&-17&28&-12\\& & 9& -24& \color{blue}{12} \\ \hline &3&-8&\color{blue}{4}& \end{array} $$Step 7 : Add down last column: $ \color{orangered}{ -12 } + \color{orangered}{ 12 } = \color{orangered}{ 0 } $
$$ \begin{array}{c|rrrr}3&3&-17&28&\color{orangered}{ -12 }\\& & 9& -24& \color{orangered}{12} \\ \hline &\color{blue}{3}&\color{blue}{-8}&\color{blue}{4}&\color{orangered}{0} \end{array} $$Bottom line represents the quotient $ \color{blue}{ 3x^{2}-8x+4 } $ with a remainder of $ \color{red}{ 0 } $.