College

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 :

To find the quotient of [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex], we perform polynomial long division.

1. Set Up the Division: Write the dividend [tex]\(x^4 + 5x^3 - 3x - 15\)[/tex] under the division symbol, and the divisor [tex]\(x^3 - 3\)[/tex] outside.

2. Divide the Leading Terms:
- Divide the leading term of the dividend, [tex]\(x^4\)[/tex], by the leading term of the divisor, [tex]\(x^3\)[/tex].
- [tex]\(x^4 \div x^3 = x\)[/tex].

3. Multiply and Subtract:
- Multiply the entire divisor [tex]\(x^3 - 3\)[/tex] by [tex]\(x\)[/tex], giving [tex]\(x(x^3 - 3) = x^4 - 3x\)[/tex].
- Subtract this result from the dividend:
[tex]\[
(x^4 + 5x^3 - 3x - 15) - (x^4 - 3x) = 5x^3 + 0x^2 + 0x - 15
\][/tex]

4. Bring Down the Next Term: There’s no x-squared term to bring down, so we deal directly with [tex]\(5x^3\)[/tex].

5. Repeat the Process:
- Divide the new leading term [tex]\(5x^3\)[/tex] by [tex]\(x^3\)[/tex].
- [tex]\(5x^3 \div x^3 = 5\)[/tex].

6. Multiply and Subtract Again:
- Multiply the divisor by [tex]\(5\)[/tex], giving [tex]\(5(x^3 - 3) = 5x^3 - 15\)[/tex].
- Subtract this from the current dividend remainder:
[tex]\[
(5x^3 - 15) - (5x^3 - 15) = 0
\][/tex]

Since there is no remainder, the division process ends here.

Conclusion: The quotient of [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex] is [tex]\(x + 5\)[/tex].

So, the correct answer from the options is [tex]\(x + 5\)[/tex].