Distributive Property on Fractions: Swapping Denominators

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I'm learning Algebra and am curious about some methodological fundamentals here. One, in particular is why the following equation:

6(2x + 1 / 3) = 6(x + 4 / 2)

results in:

2(2x + 1) = 3(x + 4)

It's obvious that the distributive property swaps the numerators of the fractions and chooses to use another distributive property to complete the equation. Is there a specific formula for this, and why does it work that way specifically?

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0
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$$a \left(\frac b c\right) = \frac a1 \frac b c = \frac {ab}{1c} = \frac {ab}{c1} = \frac ac \frac b1 = \frac ac b$$

2
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HINT $\ $ Apply the associative law $\rm\displaystyle\ \ A\ \bigg(\!\frac{1}{B}\ C\bigg)\ =\ \bigg(A\ \frac{1}B\bigg)\ C$

0
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May be the following steps help you see how you get the result from the given expression - Swapping is fine as long as you understand the meaning of it so that you don't make mistakes.

Given:

$6 \left ( \frac{2x+1}{3} \right )= 6 \left ( \frac{x+4}{2} \right )$

a-multiply both sides by 1/6 to get:

$ \left ( \frac{2x+1}{3} \right )= \left ( \frac{x+4}{2} \right )$

b-multiply both sides by 3 to get:

$ 3\left ( \frac{2x+1}{3} \right )= 3 \left ( \frac{x+4}{2} \right )$

c-This is equal to:

$ \left ( \frac{2x+1}{1} \right )= 3 \left ( \frac{x+4}{2} \right )$

d-Multiply both sides by 2

$2 \left ( \frac{2x+1}{1} \right )= 2 * 3 \left ( \frac{x+4}{2} \right )$

e-Simplifying the right hand side you get

$2 \left ( \frac{2x+1}{1} \right )= 3 \left ( \frac{x+4}{1} \right )$

f-Which is:

$2(2x+1)=3(x+4)$