Concept:
Inverse image means solving:
\[
f(x) = 5
\]
Step 1: Set equation.
\[
x^2 - 10x - 19 = 5
\]
Step 2: Simplify.
\[
x^2 - 10x - 24 = 0
\]
Step 3: Factorize.
\[
x^2 - 10x - 24 = (x-12)(x+2)=0
\]
Step 4: Solve.
\[
x = 12, -2
\]
\[
f^{-1}(5)=\{-2,12\}
\]