If the Laplace transform of a function \( f(t) \) is given by \( \dfrac{s + 3}{(s + 1)(s + 2)}, \) then \( f(0) \) is

Given \[ \int_{-\infty}^{\infty} e^{-x^2}\, dx = \sqrt{\pi}. \] If $a$ and $b$ are positive integers, the value of
\(\int_{-\infty}^{\infty} e^{-a(x+b)^2}\, dx \text{ is} \)______