Question

Simplify the surd ( 2+√5) (1+√5)​

Answer 1

$\rightarrow\tt{(2 + \sqrt{5}) \: (1 + \sqrt{5} )}$

$\rightarrow \tt{2(1 + \sqrt{5}) + \sqrt{5}(1 + \sqrt{5} ) }$

$\rightarrow \tt{2 + 2 \sqrt{5} + \sqrt{5} + 5}$

$\rightarrow \tt \boxed {\red{7 + 3 \sqrt{5} }}$

Answer 2

$\sf{(2 + \sqrt{5}) \: (1 + \sqrt{5} )}$

$\sf{2(1 + \sqrt{5}) + \sqrt{5}(1 + \sqrt{5})}$

$\sf{2 + 2 \sqrt{5} + \sqrt{5} + 5}$

$\sf\blue{7 + 3 \sqrt{5}}$