Question

15/root10+root20+root40-root5-root80 ifroot5=2.236 and root10=3.162

Answer 1

$Given\ \sqrt5=2.236,\ \ \sqrt{10}=3.162\\\\N=\frac{15}{\sqrt{10}}+\sqrt{20}+\sqrt{40}-\sqrt5-\sqrt{80}\\\\N=\frac{15}{\sqrt{10}}+\sqrt{2^2*5}+\sqrt{2^2*10}-\sqrt5-\sqrt{4^2*5}\\\\N=\frac{15}{\sqrt{10}}+2*\sqrt{5}+2*\sqrt{10}-\sqrt{5}-4*\sqrt5\\\\N=\frac{15}{\sqrt{10}}-3*\sqrt5+2*\sqrt{10}\\\\N=\frac{15}{3.162}-3*2.236+2*3.162\\\\N=4.3598\ \ or,\ 4.360$