Answer
$x=36$
Work Step by Step
Add $\sqrt{x}$ on both sides.
$\sqrt{x-11}=\sqrt{x}-1$
Square both sides.
$x-11=(\sqrt{x}-1)^2$
$x-11=x-2\sqrt{x}+1$
$2\sqrt{x}=12$
$\sqrt{x}=6$
Square both sides
$x=36$
Check:
$\sqrt{36-11}-\sqrt{36}\stackrel{?}{=}-1$
$\sqrt{25}-6\stackrel{?}{=}-1$
$5-6\stackrel{?}{=}-1$
$-1=-1\checkmark$
