Divide using synthetic division $$ ( 2x^{2}+5x-23 ) \div ( x+5 ) $$
Answer
The synthetic division table is:
$$ \begin{array}{c|rrr}-5&2&5&-23\\& & -10& \color{black}{25} \\ \hline &\color{blue}{2}&\color{blue}{-5}&\color{orangered}{2} \end{array} $$The solution is:
$$ \frac{ 2x^{2}+5x-23 }{ x+5 } = \color{blue}{2x-5} ~+~ \frac{ \color{red}{ 2 } }{ x+5 } $$Explanation
Step 1 : Write down the coefficients of the dividend into division table. Put the zero from $ x + 5 = 0 $ ( $ x = \color{blue}{ -5 } $ ) at the left.
$$ \begin{array}{c|rrr}\color{blue}{-5}&2&5&-23\\& & & \\ \hline &&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrr}-5&\color{orangered}{ 2 }&5&-23\\& & & \\ \hline &\color{orangered}{2}&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -5 } \cdot \color{blue}{ 2 } = \color{blue}{ -10 } $.
$$ \begin{array}{c|rrr}\color{blue}{-5}&2&5&-23\\& & \color{blue}{-10} & \\ \hline &\color{blue}{2}&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ 5 } + \color{orangered}{ \left( -10 \right) } = \color{orangered}{ -5 } $
$$ \begin{array}{c|rrr}-5&2&\color{orangered}{ 5 }&-23\\& & \color{orangered}{-10} & \\ \hline &2&\color{orangered}{-5}& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -5 } \cdot \color{blue}{ \left( -5 \right) } = \color{blue}{ 25 } $.
$$ \begin{array}{c|rrr}\color{blue}{-5}&2&5&-23\\& & -10& \color{blue}{25} \\ \hline &2&\color{blue}{-5}& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ -23 } + \color{orangered}{ 25 } = \color{orangered}{ 2 } $
$$ \begin{array}{c|rrr}-5&2&5&\color{orangered}{ -23 }\\& & -10& \color{orangered}{25} \\ \hline &\color{blue}{2}&\color{blue}{-5}&\color{orangered}{2} \end{array} $$Bottom line represents the quotient $ \color{blue}{ 2x-5 } $ with a remainder of $ \color{red}{ 2 } $.