Answer
When $x = -1$ or $x = -3$, the expression will be undefined.
Work Step by Step
Now, $\frac{x + 5}{x^2 + 4x + 3}$ = $\frac{x + 5}{(x + 3)(x + 1)}$,
so, when $x = -1$ or $x = -3$, the expression will be undefined since the denominator is zero.
