What is the missing number in the synthetic division problem below?

\begin{tabular}{rrrc}
\hline
2 & -2 & 3 & 4 \\
& 4 & 4 & 14 \\
\hline
2 & 2 & [tex]$?$[/tex] & 18
\end{tabular}

A. 4
B. 7
C. -1
D. 2



Answer :

To determine the missing number in the synthetic division table, let's follow the steps involved in synthetic division. The provided synthetic division table suggests it represents the division of a polynomial by [tex]\( x - 2 \)[/tex].

Here's the synthetic division process in detail:

1. Start with the polynomial coefficients: 2, -2, 3, and 4.
2. We are dividing by [tex]\( x - 2 \)[/tex], so we use the root [tex]\( 2 \)[/tex] for synthetic division.

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & 4 & 4 & 14 \\ \hline & 2 & 2 & ? & 18 \end{array} \][/tex]

To fill in the missing number, follow these steps:

1. Bring down the first coefficient (2) unchanged:

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & & & \\ \hline & 2 & & & \end{array} \][/tex]

2. Multiply the root (2) by the value just written down (2) and write the result (4) under the next coefficient:

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & 4 & & \\ \hline & 2 & & & \end{array} \][/tex]

3. Add the second coefficient (-2) to this product (4) to get 2:

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & 4 & & \\ \hline & 2 & 2 & & \end{array} \][/tex]

4. Multiply the root (2) by the value just written down (2) to get 4, then write this product under the next coefficient:

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & 4 & 4 & \\ \hline & 2 & 2 & & \end{array} \][/tex]

5. Add the third coefficient (3) to the product (4) to find the missing number, which is 7:

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & 4 & 4 & \\ \hline & 2 & 2 & 7 & \end{array} \][/tex]

6. Finally, multiply the root (2) by the number just written down (7) to get 14, and add it to the next coefficient (4) to get 18:

[tex]\[ \begin{array}{r|rrrr} 2 & 2 & -2 & 3 & 4 \\ & & 4 & 4 & 14 \\ \hline & 2 & 2 & 7 & 18 \end{array} \][/tex]

Thus, the missing number is
[tex]\[ 7 \][/tex]

Therefore, the answer is [tex]\( \boxed{7} \)[/tex].