Question

Simplify the following expressions:
$(\sqrt{5}-\sqrt{2})(\sqrt{5}+\sqrt{2})$

Answer 1

$(\sqrt{5}+\sqrt{2})(\sqrt{5}-\sqrt{2})$

We know that $(a+b)(a-b)=a^2-b^2$

$=(\sqrt{5}+\sqrt{2})(\sqrt{5}-\sqrt{2})$

$=(\sqrt{5}{)}^2-(\sqrt{2}{)}^2$

$=5-2$

$=3$