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