The image you've uploaded contains a mathematical function $f(x)$, and the task is to determine its value at certain points. The expression seems to be:

$f(x) = \frac{x}{1 - x^2}$

And the questions are asking to find the values for:

1. $f\left(\frac{1}{2}\right)$
2. $f(x + 2)$
3. $f\left(\frac{a}{b}\right)$

Let me solve each of these for you.

1. Finding $f\left(\frac{1}{2}\right)$

Substitute $x = \frac{1}{2}$ into the function:

$f\left(\frac{1}{2}\right) = \frac{\frac{1}{2}}{1 - \left(\frac{1}{2}\right)^2} = \frac{\frac{1}{2}}{1 - \frac{1}{4}} = \frac{\frac{1}{2}}{\frac{3}{4}} = \frac{1}{2} \times \frac{4}{3} = \frac{2}{3}$

2. Finding $f(x + 2)$

Substitute $x + 2$ for $x$ in the function:

$f(x+2) = \frac{x+2}{1 - (x+2)^2}$

This is the general form, and it can be expanded further if needed.

3. Finding $f\left(\frac{a}{b}\right)$

Substitute $x = \frac{a}{b}$ into the function:

$f\left(\frac{a}{b}\right) = \frac{\frac{a}{b}}{1 - \left(\frac{a}{b}\right)^2} = \frac{\frac{a}{b}}{1 - \frac{a^2}{b^2}} = \frac{\frac{a}{b}}{\frac{b^2 - a^2}{b^2}} = \frac{a}{b} \times \frac{b^2}{b^2 - a^2} = \frac{ab}{b^2 - a^2}$

Let me know if you'd like more detailed steps or clarifications on any of these steps! Would you like me to expand or explain further?