a/ $\sqrt{(2-\sqrt 3)^2}=|2-\sqrt 3|=2-\sqrt 3$
b/ $\sqrt{(3-\sqrt{10})^2}=|3-\sqrt{10}|=\sqrt{10}-3$
c/ $2\sqrt{a^2}=2|a|$
mà $a<0$
$→2\sqrt{a^2}=-2a$
d/ $3\sqrt{(a-2)^2}=3|a-2|$
Vì $a≥2→a-2≥0→2\sqrt{(a-2)^2}=3(a-2)$
e/ $\sqrt{(x-2)^2}-1\\=|x-2|-1$
$|x-2|=\begin{cases}x-2\,\,nếu\,\,x-2\ge 0\,\,hay\,\,x\ge 2\\2-x\,\,nếu\,\,x-2<0\,\,hay\,\,x<2\end{cases}$
TH1: $x\ge 2→\sqrt{(x-2)^2}-1=x-2-1=x-3$
TH2: $x<2→\sqrt{(x-2)^2}-1=2-x-1=1-x$
