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