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