The inverse Laplace transform of $${1 \over {\left( {{s^2} + s} \right)}}$$ is

If $$F(s)$$ is the Laplace transform of the function $$f(t)$$ then Laplace transform of $$\int\limits_0^t {f\left( x \right)dx} $$ is

Laplace transform of $${\left( {a + bt} \right)^2}$$ where $$'a'$$ and $$'b'$$ are constants is given by:

Solve the initial value problem
$${{{d^2}y} \over {d{x^2}}} - 4{{dy} \over {dx}} + 3y = 0$$ with $$y=3$$ and
$${{dy} \over {dx}} = 7$$ at $$x=0$$ using the laplace transform technique?