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 solve this problem, we need to find the quotient obtained when dividing the polynomial [tex]\( x^4 + 5x^3 - 3x - 15 \)[/tex] by [tex]\( x^3 - 3 \)[/tex].

Here is the step-by-step solution:

1. Set up the division:
We're dividing [tex]\( x^4 + 5x^3 - 3x - 15 \)[/tex] by [tex]\( x^3 - 3 \)[/tex].

2. Look at the leading terms:
- The leading term of the dividend is [tex]\( x^4 \)[/tex].
- The leading term of the divisor is [tex]\( x^3 \)[/tex].

3. Divide the leading terms:
Divide [tex]\( x^4 \)[/tex] by [tex]\( x^3 \)[/tex], which gives [tex]\( x \)[/tex].

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

5. Repeat the process:
- Now, our new dividend is [tex]\( 5x^3 - 15 \)[/tex].

6. Divide again:
This time, divide [tex]\( 5x^3 \)[/tex] by [tex]\( x^3 \)[/tex], which gives [tex]\( 5 \)[/tex].

7. Multiply and subtract:
Multiply [tex]\( 5 \)[/tex] by the divisor:
[tex]\[
(5)(x^3 - 3) = 5x^3 - 15
\][/tex]
Subtract this from [tex]\( 5x^3 - 15 \)[/tex]:
[tex]\[
(5x^3 - 15) - (5x^3 - 15) = 0
\][/tex]

8. Conclusion:
The division results in a quotient of [tex]\( x + 5 \)[/tex] with a remainder of 0.

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