What is the quotient of the rational expression below?

[tex] \frac{x-4}{3x^2} \div \frac{12x+1}{x+3} [/tex]

A. [tex] \frac{x^2-x-4}{12x^3+x^2} [/tex]

B. [tex] \frac{x^2-x-12}{36x^3+1} [/tex]

C. [tex] \frac{x^2-x-12}{36x^3+3x^2} [/tex]

D. [tex] \frac{x^2+7x-12}{36x^3+3x^2} [/tex]



Answer :

To find the quotient of the given rational expression:

[tex]\[ \frac{x-4}{3 x^2} \div \frac{12 x+1}{x+3} \][/tex]

we can follow these steps:

1. Recall that dividing by a fraction is the same as multiplying by its reciprocal. So, the given expression is equivalent to:

[tex]\[ \frac{x-4}{3 x^2} \cdot \frac{x+3}{12 x+1} \][/tex]

2. Next, we multiply the numerators together and the denominators together:

[tex]\[ \text{Numerator: } (x-4)(x+3) \][/tex]
[tex]\[ \text{Denominator: } (3 x^2)(12 x+1) \][/tex]

3. We can now represent the product as a single fraction:

[tex]\[ \frac{(x-4)(x+3)}{3 x^2 (12 x+1)} \][/tex]

4. Let’s simplify the numerator and the denominator if possible.

First, expand the numerator:

[tex]\[ (x-4)(x+3) = x^2 + 3x - 4x - 12 = x^2 - x - 12 \][/tex]

Now, the denominator:

[tex]\[ 3 x^2 (12 x+1) = 36 x^3 + 3 x^2 \][/tex]

So, the simplified quotient becomes:

[tex]\[ \frac{x^2 - x - 12}{36 x^3 + 3 x^2} \][/tex]

5. Hence, the simplified form of the given rational expression is:

[tex]\[ \frac{x^2 - x - 12}{36 x^3 + 3 x^2} \][/tex]

Therefore, the correct answer is:

C. [tex]\(\frac{x^2 - x - 12}{36 x^3 + 3 x^2}\)[/tex]