Question

Simplify the following:

Square of the answer of ($\sqrt{45}-3\sqrt{20}+4\sqrt{5}$) is

Answer 1

$=\sqrt{3\times 3\times 5}-3\sqrt{2\times 2\times 5}+4\sqrt{5}$
$=3\sqrt{5}-6\sqrt{5}+4\sqrt{5}$
$=\sqrt{5}$

So, $(\sqrt{5}{)}^2=5$