Answer:
[tex]$-4x$[/tex]
Step-by-step explanation:
First, let us write this equation into an easier one. We have:
[tex]$-\sqrt{16x^2}=-\sqrt{4^2x^2}$[/tex]
The exponents cancel out with the square root, so we have:
[tex]-4x[/tex]
as our answer.
HOPE IT HELPS :D