Question Number 100369 by Fikret last updated on 26/Jun/20
$${a}\epsilon\mathbb{Z}\:\:\:\mathrm{0}<{b}<\mathrm{1}\:\:\:\: \\ $$$${a}+{b}=\sqrt{\mathrm{20}} \\ $$$${b}^{\mathrm{2}} +\mathrm{4}{b}+\mathrm{8}\sqrt{\mathrm{5}}=? \\ $$
Answered by MJS last updated on 26/Jun/20
$$\sqrt{\mathrm{20}}\approx\mathrm{4}.\mathrm{47} \\ $$$$\Rightarrow\:{a}=\mathrm{4}\wedge{b}=−\mathrm{4}+\sqrt{\mathrm{20}} \\ $$$$\Rightarrow\:\mathrm{snswer}\:\mathrm{is}\:\mathrm{20} \\ $$