Answer
$x=-1$
Work Step by Step
$y=|x|$ is an absolute value function with axis of symmetry $x=0$.
$y=|x+1|$ is a translation of $y=|x|$ one unit to the left.
So, axis of symmetry will move one unit left as well and becomes $x=-1$.
$y=-|x+1|$ is a reflection over $x$-axis of $y=|x+1|$.
Note, that axis of symmetry will remain the same in this case.
So, it is $x=-1$.
