The solutions of the differential equation $${{{d^2}y} \over {d{x^2}}} + 2{{dy} \over {dx}} + 2y = 0\,\,$$ are

The value of the expression $${{ - 5 + 10i} \over {3 + 4i}}$$ is

Laplace transform of $$8$$ $${t^3}$$ is

Laplace transform of $$sin$$ $$ht$$ is