Which expression is equivalent to [tex]\(\frac{2a+1}{10a-5} \div \frac{10a}{4a^2-1}\)[/tex]?

A. [tex]\(\frac{2a}{(2a-1)^2}\)[/tex]

B. [tex]\(\frac{50a}{(2a+1)^2}\)[/tex]

C. [tex]\(\frac{(2a-1)^2}{2a}\)[/tex]

D. [tex]\(\frac{(2a+1)^2}{50a}\)[/tex]



Answer :

Let's determine the equivalent expression for the given problem:

[tex]\[ \frac{2a + 1}{10a - 5} \div \frac{10a}{4a^2 - 1} \][/tex]

Step-by-step:

1. Understanding the problem:
We are given the expression [tex]\(\frac{2a + 1}{10a - 5} \div \frac{10a}{4a^2 - 1}\)[/tex]. Recall that division by a fraction is equivalent to multiplication by its reciprocal.

2. Rewrite the division as multiplication by the reciprocal:
[tex]\[ \frac{2a + 1}{10a - 5} \div \frac{10a}{4a^2 - 1} = \frac{2a + 1}{10a - 5} \times \frac{4a^2 - 1}{10a} \][/tex]

3. Simplify the reciprocal expression:
Notice that [tex]\(4a^2 - 1\)[/tex] is a difference of squares:
[tex]\[ 4a^2 - 1 = (2a - 1)(2a + 1) \][/tex]
Thus,
[tex]\[ \frac{2a + 1}{10a - 5} \times \frac{(2a - 1)(2a + 1)}{10a} \][/tex]

4. Combine the fractions:
[tex]\[ \frac{(2a + 1)(2a + 1)(2a - 1)}{(10a - 5) \times 10a} \][/tex]

5. Simplify the result:
Observe that [tex]\(10a - 5 = 5(2a - 1)\)[/tex], so the expression becomes:
[tex]\[ \frac{(2a + 1)^2 (2a - 1)}{50a (2a - 1)} \][/tex]
The [tex]\((2a - 1)\)[/tex] term cancels out:
[tex]\[ \frac{(2a + 1)^2}{50a} \][/tex]

Thus, the expression equivalent to [tex]\(\frac{2a + 1}{10a - 5} \div \frac{10a}{4a^2 - 1}\)[/tex] is:

[tex]\[ \frac{(2a + 1)^2}{50a} \][/tex]

So, the correct answer is:

[tex]\[ \boxed{\frac{(2a+1)^2}{50a}} \][/tex]

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