Use Laplace transforms to solve the following initial value problem.

$x^{(3)}{x}^{\text{'}\text{'}}-56x^{\text{'}}=0$;$x(0)=0,x^{\text{'}}(0)=x^{\text{'}\text{'}}(0)=3$

First find the Laplace transform of $x(t).$

$x(s)=$

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