High School

What is the remainder in the synthetic division problem below?

[tex]
1 \div \begin{array}{c|ccc}
& 4 & 6 & -3 \\
\end{array}
[/tex]

A. 5
B. 7
C. 3
D. 9

Answer :

Certainly! Let's take a detailed look at how to use synthetic division to find the remainder for the given problem.

We are dividing the polynomial represented by the coefficients [tex]\(4x^2 + 6x - 3\)[/tex] by [tex]\(x - 1\)[/tex].

Step 1: Set up the synthetic division.

- Use the value [tex]\(1\)[/tex] from [tex]\(x - 1\)[/tex]. This is because synthetic division uses the root of the divisor, which in this case is [tex]\(x = 1\)[/tex].

- Write down the coefficients of the polynomial: [tex]\(4, 6, -3\)[/tex].

```
1 | 4 6 -3
```

Step 2: Begin the process.

1. Bring down the first coefficient [tex]\(4\)[/tex] as it is.

```
| 4 6 -3
1 |-------------
| 4
```

2. Multiply the root, [tex]\(1\)[/tex], by the number you just brought down, [tex]\(4\)[/tex], and write the result under the next coefficient:

[tex]\(1 \times 4 = 4\)[/tex]

```
| 4 6 -3
1 | 4
|-------------
| 4
```

3. Add this result to the next coefficient [tex]\(6\)[/tex]:

[tex]\(6 + 4 = 10\)[/tex]

```
| 4 6 -3
1 | 4
|-------------
| 4 10
```

4. Multiply the root, [tex]\(1\)[/tex], by this new value [tex]\(10\)[/tex] and write the result under the next coefficient:

[tex]\(1 \times 10 = 10\)[/tex]

```
| 4 6 -3
1 | 4 10
|-------------
| 4 10
```

5. Add this result to the last coefficient [tex]\(-3\)[/tex]:

[tex]\(-3 + 10 = 7\)[/tex]

```
| 4 6 -3
1 | 4 10
|-------------
| 4 10 7
```

Step 3: Find the remainder.

The last number you obtain in the bottom row is the remainder. In this case, the remainder is [tex]\(7\)[/tex].

Therefore, the correct answer is B. 7.