What is the quotient of the rational expression below?

[tex]\[
\frac{3x+1}{x+8} \div \frac{x-7}{5x}
\][/tex]

A. [tex]\(\frac{3x^2 + x}{x^2 + x - 56}\)[/tex]

B. [tex]\(\frac{15x^2 + 1}{x^2 + x - 56}\)[/tex]

C. [tex]\(\frac{15x^2 + 5x}{x^2 + 15x - 56}\)[/tex]

D. [tex]\(\frac{15x^2 + 5x}{x^2 + x - 56}\)[/tex]



Answer :

To determine the quotient of the rational expression [tex]\(\frac{3x + 1}{x + 8} \div \frac{x - 7}{5x}\)[/tex], we proceed with the following steps:

1. Rewrite the Division as Multiplication:
Division of fractions can be converted into multiplication by the reciprocal. Therefore:
[tex]\[ \frac{3 x + 1}{x + 8} \div \frac{x - 7}{5 x} = \frac{3 x + 1}{x + 8} \times \frac{5 x}{x - 7} \][/tex]

2. Multiply the Numerators Together:
Multiply the numerators of the two rational expressions:
[tex]\[ (3 x + 1) \times 5 x = 5 x (3 x + 1) \][/tex]
Simplifying the product:
[tex]\[ 5 x (3 x + 1) = 15 x^2 + 5 x \][/tex]

3. Multiply the Denominators Together:
Similarly, multiply the denominators of the two rational expressions:
[tex]\[ (x + 8) \times (x - 7) \][/tex]
Expanding the product using the distributive property (FOIL):
[tex]\[ (x + 8)(x - 7) = x^2 - 7x + 8x - 56 = x^2 + x - 56 \][/tex]

4. Form the New Rational Expression:
Place the simplified numerator and denominator into a single fraction:
[tex]\[ \frac{15 x^2 + 5 x}{x^2 + x - 56} \][/tex]

Therefore, the quotient of the given rational expression is:
[tex]\[ \boxed{\frac{15 x^2 + 5 x}{x^2 + x - 56}} \][/tex]

The answer corresponds to option D.