To evaluate the function \( f(x) = -x^2 - 4 \) for \( x = -3 \), we substitute \(-3\) into the function.
\[ f(-3) = -(-3)^2 - 4 \]
Now, calculate \((-3)^2\):
\[ (-3)^2 = 9 \]
Substituting back into the equation gives:
\[ f(-3) = -9 - 4 \]
Now, simplify:
\[ f(-3) = -13 \]
So, the value of \( f(-3) \) is \(-13\).