College

The quotient of [tex]$x^4+5x^3-3x-15$[/tex] and [tex]$x^3-3$[/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] divided by [tex]\((x^3 - 3)\)[/tex], we can use polynomial long division. Here's a detailed, step-by-step solution:

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

3. Multiply and subtract: Multiply the entire divisor [tex]\((x^3 - 3)\)[/tex] by the result [tex]\(x\)[/tex], which gives [tex]\(x \cdot (x^3 - 3) = x^4 - 3x\)[/tex]. Subtract this from the original polynomial:

[tex]\[
(x^4 + 5x^3 - 3x - 15) - (x^4 - 3x) = 5x^3 + 0 - 15
\][/tex]

4. Repeat the process: Now divide [tex]\(5x^3\)[/tex] by [tex]\(x^3\)[/tex], which gives [tex]\(5\)[/tex]. Multiply the entire divisor by [tex]\(5\)[/tex] to get [tex]\(5(x^3 - 3) = 5x^3 - 15\)[/tex].

5. Subtract again:

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

Since we have reached a remainder of [tex]\(0\)[/tex], the division is complete. The quotient of the division is the sum of the individual quotients obtained in the steps:

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

Therefore, the answer is [tex]\(x + 5\)[/tex].