Find remainder when $ x^{3}-10x^{2}+26x-3 $ is divided by $ x-4 $.
Answer
The synthetic division table is:
$$ \begin{array}{c|rrrr}4&1&-10&26&-3\\& & 4& -24& \color{black}{8} \\ \hline &\color{blue}{1}&\color{blue}{-6}&\color{blue}{2}&\color{orangered}{5} \end{array} $$The remainder when $ x^{3}-10x^{2}+26x-3 $ is divided by $ x-4 $ is $ \, \color{red}{ 5 } $.
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 -4 = 0 $ ( $ x = \color{blue}{ 4 } $ ) at the left.
$$ \begin{array}{c|rrrr}\color{blue}{4}&1&-10&26&-3\\& & & & \\ \hline &&&& \end{array} $$Step 1 : Bring down the leading coefficient to the bottom row.
$$ \begin{array}{c|rrrr}4&\color{orangered}{ 1 }&-10&26&-3\\& & & & \\ \hline &\color{orangered}{1}&&& \end{array} $$Step 2 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 4 } \cdot \color{blue}{ 1 } = \color{blue}{ 4 } $.
$$ \begin{array}{c|rrrr}\color{blue}{4}&1&-10&26&-3\\& & \color{blue}{4} & & \\ \hline &\color{blue}{1}&&& \end{array} $$Step 3 : Add down last column: $ \color{orangered}{ -10 } + \color{orangered}{ 4 } = \color{orangered}{ -6 } $
$$ \begin{array}{c|rrrr}4&1&\color{orangered}{ -10 }&26&-3\\& & \color{orangered}{4} & & \\ \hline &1&\color{orangered}{-6}&& \end{array} $$Step 4 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 4 } \cdot \color{blue}{ \left( -6 \right) } = \color{blue}{ -24 } $.
$$ \begin{array}{c|rrrr}\color{blue}{4}&1&-10&26&-3\\& & 4& \color{blue}{-24} & \\ \hline &1&\color{blue}{-6}&& \end{array} $$Step 5 : Add down last column: $ \color{orangered}{ 26 } + \color{orangered}{ \left( -24 \right) } = \color{orangered}{ 2 } $
$$ \begin{array}{c|rrrr}4&1&-10&\color{orangered}{ 26 }&-3\\& & 4& \color{orangered}{-24} & \\ \hline &1&-6&\color{orangered}{2}& \end{array} $$Step 6 : Multiply by the number on the left, and carry the result into the next column: $ \color{blue}{ 4 } \cdot \color{blue}{ 2 } = \color{blue}{ 8 } $.
$$ \begin{array}{c|rrrr}\color{blue}{4}&1&-10&26&-3\\& & 4& -24& \color{blue}{8} \\ \hline &1&-6&\color{blue}{2}& \end{array} $$Step 7 : Add down last column: $ \color{orangered}{ -3 } + \color{orangered}{ 8 } = \color{orangered}{ 5 } $
$$ \begin{array}{c|rrrr}4&1&-10&26&\color{orangered}{ -3 }\\& & 4& -24& \color{orangered}{8} \\ \hline &\color{blue}{1}&\color{blue}{-6}&\color{blue}{2}&\color{orangered}{5} \end{array} $$Remainder is the last entry in the bottom row $ \left(\color{red}{ 5 }\right) $.