Which expression is equivalent to [tex]\frac{3 x}{x+1}[/tex] divided by [tex]x+1[/tex]?

A. [tex]\frac{3 x}{x+1} \cdot \frac{1}{x+1}[/tex]
B. [tex]\frac{3 x}{x+1} \div \frac{1}{x+1}[/tex]
C. [tex]\frac{x+1}{1} \div \frac{3 x}{x+1}[/tex]
D. [tex]\frac{x+1}{3 x} \cdot \frac{x+1}{1}[/tex]



Answer :

To determine which expression is equivalent to [tex]\(\frac{3x}{x+1}\)[/tex] divided by [tex]\(x+1\)[/tex], let's break down the process step by step.

1. Original Expression:
We start with [tex]\(\frac{3x}{x+1}\)[/tex] divided by [tex]\(x+1\)[/tex]. This can be written as:
[tex]\[ \frac{\frac{3x}{x+1}}{x+1} \][/tex]

2. Simplify the Complex Fraction:
To simplify the complex fraction, we can multiply by the reciprocal. That is:
[tex]\[ \frac{\frac{3x}{x+1}}{x+1} = \frac{3x}{x+1} \cdot \frac{1}{x+1} \][/tex]

This means our expression becomes:
[tex]\[ \frac{3x}{(x+1)^2} \][/tex]

3. Compare with Given Choices:
We need to match this simplified form [tex]\(\frac{3x}{(x+1)^2}\)[/tex] with one of the given choices.

- Choice 1: [tex]\(\frac{3x}{x+1} \cdot \frac{1}{x+1}\)[/tex]

If we simplify this, we have:
[tex]\[ \frac{3x}{x+1} \cdot \frac{1}{x+1} = \frac{3x}{(x+1)^2} \][/tex]
This matches our simplified form.

- Choice 2: [tex]\(\frac{3x}{x+1} \div \frac{1}{x+1}\)[/tex]

This involves division by a fraction, which is the same as multiplying by its reciprocal.
[tex]\[ \frac{3x}{x+1} \div \frac{1}{x+1} = \frac{3x}{x+1} \cdot \frac{x+1}{1} = 3x \][/tex]
This does not match our simplified form.

- Choice 3: [tex]\(\frac{x+1}{1} \div \frac{3x}{x+1}\)[/tex]

Again, this involves division by a fraction:
[tex]\[ \frac{x+1}{1} \div \frac{3x}{x+1} = \frac{x+1}{1} \cdot \frac{x+1}{3x} = \frac{(x+1)^2}{3x} \][/tex]
This does not match our simplified form.

- Choice 4: [tex]\(\frac{x+1}{3x} \cdot \frac{x+1}{1}\)[/tex]

Simplifying this:
[tex]\[ \frac{x+1}{3x} \cdot \frac{x+1}{1} = \frac{(x+1)^2}{3x} \][/tex]
This does not match our simplified form.

4. Conclusion:
The correct equivalent expression is:
[tex]\[ \frac{3x}{x+1} \cdot \frac{1}{x+1} \][/tex]

Therefore, the correct choice is:
[tex]\[ \boxed{1} \][/tex]

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