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

Here's a step-by-step guide on how to do it:

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

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]).
- This gives you the first term of the quotient: [tex]\(x\)[/tex].

3. Multiply and Subtract:
- Multiply the entire divisor ([tex]\(x^3 - 3\)[/tex]) by the term [tex]\(x\)[/tex], resulting in [tex]\(x^4 - 3x\)[/tex].
- Subtract this result from the original dividend:

[tex]\[
(x^4 + 5x^3 - 3x - 15) - (x^4 - 3x) = 5x^3 + 3x - 15
\][/tex]

4. Repeat the Process:
- Now, divide the leading term of the new dividend ([tex]\(5x^3\)[/tex]) by the leading term of the divisor ([tex]\(x^3\)[/tex]).
- This gives you the next term of the quotient: [tex]\(+5\)[/tex].

5. Multiply and Subtract Again:
- Multiply the entire divisor ([tex]\(x^3 - 3\)[/tex]) by [tex]\(5\)[/tex], resulting in [tex]\(5x^3 - 15\)[/tex].
- Subtract this from the current dividend:

[tex]\[
(5x^3 + 3x - 15) - (5x^3 - 15) = 3x
\][/tex]

6. End Point:
- Since the remainder [tex]\(3x\)[/tex] has a degree ([tex]\(1\)[/tex]) less than the degree of the divisor ([tex]\(3\)[/tex]), the process stops here.

7. Final Quotient:
- The quotient is the result obtained from adding the terms you have calculated: [tex]\(x + 5\)[/tex].

So, the quotient of dividing [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] by [tex]\((x^3 - 3)\)[/tex] is [tex]\((x + 5)\)[/tex].