Step 1: Understanding the Concept:
In SHM, \(v^2 = \omega^2(A^2 - x^2)\).
Step 2: Compare:
The given relation is \(v^2 = \frac14(50 - x^2)\). So \(\omega^2 = \frac14\), giving \(\omega = \frac12\) rad/s, and \(A^2 = 50\).
Step 3: Time period:
\[ T = \frac{2\pi}{\omega} = 4\pi = 4\times\frac{22}{7} = \frac{88}{7}\ \text{s} \]
The problem says \(T = \frac{x}{7}\), so \(x = 88\).
Final Answer:
The value of \(x\) is \(88\), option (C).
\[ \boxed{88} \]