In a rectangle, the diagonals are equal in length. Therefore, we can set the two given diagonals equal to each other:
\[ AC = BD \]
Given that \(AC = 52x\) and \(BD = 2x + 5\), we can write the equation:
\[ 52x = 2x + 5 \]
Now, let's solve for \(x\):
- Subtract \(2x\) from both sides:
\[ 52x - 2x = 5 \]
\[ 50x = 5 \]
- Divide both sides by 50:
\[ x = \frac{5}{50} \]
\[ x = \frac{1}{10} \]
Thus, the value of \(x\) is
\[ \boxed{\frac{1}{10}} \]