High School

The quotient of [tex]\left(x^4 + 5x^3 - 3x - 15\right)[/tex] and [tex]\left(x^3 - 3\right)[/tex] is a polynomial. What is the quotient?

A. [tex]x^7 + 5x^6 - 6x^4 - 30x^3 + 9x + 45[/tex]
B. [tex]x - 5[/tex]
C. [tex]x + 5[/tex]
D. [tex]x^7 + 5x^6 + 6x^4 + 30x^3 + 9x + 45[/tex]

Answer :

Sure! Let's find the quotient of [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex] by performing polynomial long division.

### Steps for Polynomial Long Division:

1. Setup the Division:
[tex]\[
\frac{x^4 + 5x^3 - 3x - 15}{x^3 - 3}
\][/tex]

2. First Division Step:
- Divide the first term of the numerator [tex]\(x^4\)[/tex] by the first term of the denominator [tex]\(x^3\)[/tex]:
[tex]\[
x^4 \div x^3 = x
\][/tex]
- Multiply [tex]\(x\)[/tex] by the entire denominator [tex]\((x^3 - 3)\)[/tex]:
[tex]\[
x \cdot (x^3 - 3) = x^4 - 3x
\][/tex]
- Subtract this from the numerator:
[tex]\[
(x^4 + 5x^3 - 3x - 15) - (x^4 - 3x) = 5x^3 + 0 - 15 = 5x^3 - 15
\][/tex]

3. Second Division Step:
- Divide the first term of the new numerator [tex]\(5x^3\)[/tex] by the first term of the denominator [tex]\(x^3\)[/tex]:
[tex]\[
5x^3 \div x^3 = 5
\][/tex]
- Multiply [tex]\(5\)[/tex] by the entire denominator [tex]\((x^3 - 3)\)[/tex]:
[tex]\[
5 \cdot (x^3 - 3) = 5x^3 - 15
\][/tex]
- Subtract this from the new numerator:
[tex]\[
(5x^3 - 15) - (5x^3 - 15) = 0
\][/tex]

### Conclusion:
The quotient is formed from the sums of these individual steps:
[tex]\[
x + 5
\][/tex]

### Final Result:
Therefore, the quotient of [tex]\(\frac{x^4 + 5x^3 - 3x - 15}{x^3 - 3}\)[/tex] is:
[tex]\[
\boxed{x + 5}
\][/tex]