Find remainder when $ 3x^{2}+3x-5 $ is divided by $ x+2 $.
Answer
The synthetic division table is:
$$ \begin{array}{c|rrr}-2&3&3&-5\\& & -6& \color{black}{6} \\ \hline &\color{blue}{3}&\color{blue}{-3}&\color{orangered}{1} \end{array} $$The remainder when $ 3x^{2}+3x-5 $ is divided by $ x+2 $ is $ \, \color{red}{ 1 } $.
Explanation
We can find remainder using synthetic division method.
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.
$$ \begin{array}{c|rrr}\color{blue}{-2}&3&3&-5\\& & & \\ \hline &&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrr}-2&\color{orangered}{ 3 }&3&-5\\& & & \\ \hline &\color{orangered}{3}&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -2 } \cdot \color{blue}{ 3 } = \color{blue}{ -6 } $.
$$ \begin{array}{c|rrr}\color{blue}{-2}&3&3&-5\\& & \color{blue}{-6} & \\ \hline &\color{blue}{3}&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ 3 } + \color{orangered}{ \left( -6 \right) } = \color{orangered}{ -3 } $
$$ \begin{array}{c|rrr}-2&3&\color{orangered}{ 3 }&-5\\& & \color{orangered}{-6} & \\ \hline &3&\color{orangered}{-3}& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ -2 } \cdot \color{blue}{ \left( -3 \right) } = \color{blue}{ 6 } $.
$$ \begin{array}{c|rrr}\color{blue}{-2}&3&3&-5\\& & -6& \color{blue}{6} \\ \hline &3&\color{blue}{-3}& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ -5 } + \color{orangered}{ 6 } = \color{orangered}{ 1 } $
$$ \begin{array}{c|rrr}-2&3&3&\color{orangered}{ -5 }\\& & -6& \color{orangered}{6} \\ \hline &\color{blue}{3}&\color{blue}{-3}&\color{orangered}{1} \end{array} $$Remainder is the last entry in the bottom row $ \left(\color{red}{ 1 }\right) $.