To solve the equation \( x^2 = \frac{36}{169} \) by inspection, we take the square root of both sides.
First, we simplify the right side:
\[ x = \pm \sqrt{\frac{36}{169}} \]
Next, we can separate the square root:
\[ x = \pm \frac{\sqrt{36}}{\sqrt{169}} = \pm \frac{6}{13} \]
Thus, the solutions are:
\[ x = \frac{6}{13} \quad \text{and} \quad x = -\frac{6}{13} \]
Therefore, the correct solution set is:
\[ {-\frac{6}{13}, \frac{6}{13}} \]
So the final answer is:
\({-\frac{6}{13}, \frac{6}{13}}\)