Find left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis when lower f left-parenthesis x right-parenthesis equals Start Fraction 2 over x plus 3 End Fraction and lower g left-parenthesis x right-parenthesis equals Start Fraction 1 over 2x End Fraction.

(1 point)
Responses

left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction 4 x over 1 plus 6 x End Fraction
Image with alt text: left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction 4 x over 1 plus 6 x End Fraction

left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction 1 over x squared plus 3 x End Fraction
Image with alt text: left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction 1 over x squared plus 3 x End Fraction

left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction x plus 3 over 4 End Fraction
Image with alt text: left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction x plus 3 over 4 End Fraction

left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction 1 over x plus 3 End Fraction
Image with alt text: left-parenthesis lower f circle lower g right-parenthesis left-parenthesis x right-parenthesis equals Start Fraction 1 over x plus 3 End Fraction

1 answer

To find \((f \circ g)(x)\), we need to substitute \(g(x)\) into \(f(x)\).

We have:

\[ f(x) = \frac{2}{x + 3} \]

\[ g(x) = \frac{1}{2x} \]

Now, we find \(f(g(x))\):

\[ f(g(x)) = f\left(\frac{1}{2x}\right) = \frac{2}{\frac{1}{2x} + 3} \]

Next, we simplify the denominator:

\[ \frac{1}{2x} + 3 = \frac{1}{2x} + \frac{3 \cdot 2x}{2x} = \frac{1 + 6x}{2x} \]

Now substituting this back into our expression for \(f(g(x))\):

\[ f(g(x)) = \frac{2}{\frac{1 + 6x}{2x}} = 2 \cdot \frac{2x}{1 + 6x} = \frac{4x}{1 + 6x} \]

Therefore, we have:

\[ (f \circ g)(x) = \frac{4x}{1 + 6x} \]

The correct response is:

\((f \circ g)(x) = \frac{4x}{1 + 6x}\)