There is no general analytical solution for quintic algebraic equations, but a Newton-Raphson numerical method can be used:
So s ≈ -1.253462
There are four other solutions as well, but these are all complex.
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Here's the graph.......https://www.desmos.com/calculator/t1f4fhif21
[Desmos shows the root to be -1.25......Alan's answer is closer to the truth....!!! ]