The solution set of the inequation

$|x+1|<3$

i.e. $\quad-3

i.e. $-3

By adding $-1$, throughout the inequality

We get,

$-3-1

i.e. $\quad-4

i.e. $\quad x \in(-4,2)$

$\therefore$ Solution set of $|x+1|<3$ is $(-4,2)$