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 [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex], we can perform polynomial long division. Here's how you can do it step-by-step:

1. Set up the division: Write [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] under the division bar and [tex]\((x^3 - 3)\)[/tex] outside the division bar.

2. Divide the leading terms: Divide the first term of the dividend ([tex]\(x^4\)[/tex]) by the first term of the divisor ([tex]\(x^3\)[/tex]). This gives [tex]\(x\)[/tex]. Write [tex]\(x\)[/tex] as the first term of the quotient.

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

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

4. Bring down the next term: Here, we only have [tex]\(5x^3 - 15\)[/tex] left.

5. Repeat the process: Divide the new leading term ([tex]\(5x^3\)[/tex]) by the leading term of the divisor ([tex]\(x^3\)[/tex]), which gives [tex]\(5\)[/tex]. Write [tex]\(5\)[/tex] as the next term of the quotient.

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

[tex]\[
(5x^3 - 15) - (5x^3 - 15) = 0
\][/tex]

7. Check the remainder: After subtraction, the remainder is [tex]\(0\)[/tex], which means the division is exact.

The final quotient is [tex]\(x + 5\)[/tex].

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