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 polynomials [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex], we will perform polynomial long division. Here is a step-by-step solution:

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

2. Divide the leading term of the dividend by the leading term of the divisor:
[tex]\[ \frac{x^4}{x^3} = x \][/tex]
So, the first term of the quotient is [tex]\(x\)[/tex].

3. Multiply the entire divisor by this term:
[tex]\[ x(x^3 - 3) = x^4 - 3x \][/tex]

4. Subtract this product from the dividend:
[tex]\[ (x^4 + 5x^3 - 3x - 15) - (x^4 - 3x) = 5x^3 - 15 \][/tex]

5. Repeat the process with the new polynomial (5x^3 - 15):

6. Divide the new leading term by the leading term of the divisor:
[tex]\[ \frac{5x^3}{x^3} = 5 \][/tex]
So, the next term of the quotient is [tex]\(5\)[/tex].

7. Multiply the entire divisor by this term:
[tex]\[ 5(x^3 - 3) = 5x^3 - 15 \][/tex]

8. Subtract this product from the new polynomial:
[tex]\[ (5x^3 - 15) - (5x^3 - 15) = 0 \][/tex]

With no remainder left after the subtraction, the quotient obtained is:
[tex]\[ x + 5 \][/tex]

Therefore, the quotient of [tex]\((x^4 + 5x^3 - 3x - 15)\)[/tex] divided by [tex]\((x^3 - 3)\)[/tex] is:
[tex]\[ \boxed{x + 5} \][/tex]