$5\sin \left( {2x + \pi } \right) \to x = \frac{\pi }{6} \to 5\sin \left( {2 \times \frac{\pi }{6} + \pi } \right)$$ = 5\sin \left( {\frac{\pi }{3} + \pi } \right) =  - 5\sin \frac{\pi }{3} =  - 5\sin \left( {{{60}^ \circ }} \right)$$ =  - 5 \times \frac{{\sqrt 3 }}{2} = \frac{{ - 5\sqrt 3 }}{2}$