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31 tháng 10 2016

5+5+5+5+5+5+5+5+5+5+5+(-5 + -2)*98624514

=5x11+(-5 + -2)x98624514

=4733976672

a: \(P=\dfrac{\sqrt{3}\left(2+\sqrt{3}\right)}{\sqrt{3}}+\dfrac{\sqrt{2}\left(\sqrt{2}-1\right)}{1}-\sqrt{3}-\sqrt{2}\)

\(=2+\sqrt{3}+2-\sqrt{2}-\sqrt{3}-\sqrt{2}\)

\(=4-2\sqrt{2}\)

b: \(N=\left(1-\dfrac{\sqrt{5}\left(\sqrt{5}+1\right)}{\sqrt{5}+1}\right)\left(\dfrac{-\sqrt{5}\left(1-\sqrt{5}\right)}{1-\sqrt{5}}-1\right)\)

\(=\left(1-\sqrt{5}\right)\left(-\sqrt{5}-1\right)\)

\(=\left(\sqrt{5}-1\right)\left(\sqrt{5}+1\right)=5-1=4\)

 

24 tháng 8 2023

Sai rồi đấy ạ  câu P

2 tháng 11 2019

\((3\sqrt{20}-2\sqrt{80}+\frac{2}{3}\sqrt{45}-\sqrt{5}):\sqrt{5}\)

\(=\left(3\sqrt{2^2.5}-2\sqrt{4^2.5}+\frac{2}{3}\sqrt{3^2.5}-\sqrt{5}\right):\sqrt{5}\)

\(=\left(3.2\sqrt{5}-2.4\sqrt{5}+\frac{2}{3}.3\sqrt{5}\right):\sqrt{5}\)

\(=\left(6\sqrt{5}-8\sqrt{5}+2\sqrt{5}-\sqrt{5}\right):\sqrt{5}\)

\(=-\sqrt{5}:\sqrt{5}=-1\)

2 tháng 11 2019

\(\left(\frac{2+\sqrt{5}}{2-\sqrt{5}}-\frac{2-\sqrt{5}}{2+\sqrt{5}}\right).\frac{5-\sqrt{5}}{1-\sqrt{5}}\)

\(=\left(\frac{\left(2+\sqrt{5}\right)^2}{\left(2-\sqrt{5}\right)\left(2+\sqrt{5}\right)}-\frac{\left(2-\sqrt{5}\right)^2}{\left(2-\sqrt{5}\right)\left(2+\sqrt{5}\right)}\right).\frac{\sqrt{5}\left(\sqrt{5}-1\right)}{1-\sqrt{5}}\)

\(=\left(\frac{4+4\sqrt{5}+5-\left(4-4\sqrt{5}+5\right)}{4-5}\right).\frac{-\sqrt{5}\left(1-\sqrt{5}\right)}{1-\sqrt{5}}\)

\(=\frac{9+4\sqrt{5}-9+4\sqrt{5}}{-1}.\left(-\sqrt{5}\right)\)

\(-8\sqrt{5}.\left(-\sqrt{5}\right)=40\)

19 tháng 9 2018

\(\frac{5+2\sqrt{5}}{\sqrt{5}}-\frac{5+\sqrt{5}}{1+\sqrt{5}}+\left(2+\sqrt{5}\right)\)

\(=2+\sqrt{5}-\frac{5+\sqrt{5}}{1+\sqrt{5}}+2+\sqrt{5}\)

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

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

\(=4+\sqrt{5}\)

b: \(B=\dfrac{\sqrt{5}+1}{\sqrt{5}-1}+\dfrac{\sqrt{5}-1}{\sqrt{5}+1}\)

\(=\dfrac{6+2\sqrt{5}+6-2\sqrt{5}}{4}=\dfrac{12}{4}=3\)

c: \(=\sqrt{5}+\dfrac{1}{2}\cdot2\sqrt{5}+\sqrt{5}=3\sqrt{5}\)

27 tháng 10 2020

\(\frac{5+\sqrt{5}}{\sqrt{5}+2}+\frac{5}{\sqrt{5}-1}-\frac{3\sqrt{5}}{3+\sqrt{5}}\)

\(=\frac{\left(5+\sqrt{5}\right)\left(\sqrt{5}-2\right)}{5-4}+\frac{5\left(\sqrt{5}+1\right)}{5-1}-\frac{3\sqrt{5}\left(3-\sqrt{5}\right)}{9-5}\)

\(=5\sqrt{5}-10+5-2\sqrt{5}+\frac{5\sqrt{5}+5}{4}-\frac{9\sqrt{5}-15}{4}\)

\(=3\sqrt{5}-5+\frac{-4\sqrt{5}+20}{4}\)

\(=3\sqrt{5}-5-\sqrt{5}+5=2\sqrt{5}\)