Consider a continuous-time signal
\[
x(t) = -t^2 \left[ u(t+4) - u(t-4) \right]
\]
where \( u(t) \) is the continuous-time unit step function. Let \( \delta(t) \) be the continuous-time unit impulse function. The value of
\[
\int_{-\infty}^{\infty} x(t) \delta(t+3) \, dt \text{ is:}
\]