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^7+5x^6+6x^4+30x^3+9x+45[/tex]

C. [tex]x+5[/tex]

D. [tex]x-5[/tex]

Answer :

To find the quotient of the polynomial [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex], we can perform polynomial long division. Let's go through this process step-by-step:

1. Set Up the Problem:
- Dividend: [tex]\(x^4 + 5x^3 - 3x - 15\)[/tex]
- Divisor: [tex]\(x^3 - 3\)[/tex]

2. Perform Long Division:
- Look at the leading term of the dividend ([tex]\(x^4\)[/tex]) and the leading term of the divisor ([tex]\(x^3\)[/tex]).
- Divide the leading term of the dividend by the leading term of the divisor: [tex]\(\frac{x^4}{x^3} = x\)[/tex].
- This result, [tex]\(x\)[/tex], is part of the quotient.

3. Multiply and Subtract:
- Multiply the divisor [tex]\((x^3 - 3)\)[/tex] by [tex]\(x\)[/tex] to get [tex]\(x(x^3 - 3) = x^4 - 3x\)[/tex].
- Subtract this result from the original dividend:
[tex]\[
(x^4 + 5x^3 - 3x - 15) - (x^4 - 3x) = 5x^3 - 0x^2 - 3x - 15 + 3x
\][/tex]
- Simplify the expression to get the new dividend: [tex]\(5x^3 - 15\)[/tex].

4. Repeat the Process:
- Divide the leading term of the new dividend ([tex]\(5x^3\)[/tex]) by the leading term of the divisor ([tex]\(x^3\)[/tex]): [tex]\(\frac{5x^3}{x^3} = 5\)[/tex].
- This result, [tex]\(5\)[/tex], is the next term in the quotient.
- Multiply the divisor by [tex]\(5\)[/tex] to get [tex]\(5(x^3 - 3) = 5x^3 - 15\)[/tex].
- Subtract this from the new dividend:
[tex]\[
(5x^3 - 15) - (5x^3 - 15) = 0
\][/tex]

5. Conclusion:
- The remainder is [tex]\(0\)[/tex], and the division process is complete.
- 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 quotient is [tex]\(x + 5\)[/tex].