\(A=3\sqrt{2}\left(\sqrt{50}-2\sqrt{18}+\sqrt{98}\right)\)

b)

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27 tháng 7 2018

\(a.3\sqrt{2}\left(\sqrt{50}-2\sqrt{18}+\sqrt{98}\right)=30-36+42=36\)

\(b.B=\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}=\sqrt{13+30\sqrt{2+\sqrt{\left(2\sqrt{2}+1\right)^2}}}=\sqrt{13+30\sqrt{2+2\sqrt{2}+1}}=\sqrt{13+30\sqrt{\left(\sqrt{2}+1\right)^2}}=\sqrt{13+30\sqrt{2}+30}=\sqrt{25+2.5\sqrt{18}+18}=\sqrt{\left(5+\sqrt{18}\right)^2}=5+3\sqrt{2}\)

23 tháng 10 2016

c/ = \(\sqrt{13+30\sqrt{2+\sqrt{8+2.2\sqrt{2}+1}}}\)

\(=\sqrt{13+30\sqrt{3+2\sqrt{2}}}\)

\(=\sqrt{43+30\sqrt{2}}\)

\(=\sqrt{25+2.3.5.\sqrt{2}+18}\)

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

23 tháng 10 2016

d/ \(=\sqrt{13+6\sqrt{4+\sqrt{9-4\sqrt{2}}}}\)

\(=\sqrt{13+6\sqrt{4+2\sqrt{2}-1}}\)

\(=\sqrt{13+6\left(\sqrt{3}+1\right)}\)

\(=\sqrt{19+6\sqrt{2}}\)

\(=3\sqrt{2}+1\)

28 tháng 7 2016

a) \(\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}}\)

\(=\sqrt{5-\sqrt{3-\sqrt{20-2\cdot3\cdot\sqrt{20}+9}}}\)

\(=\sqrt{5-\sqrt{3-\sqrt{\left(\sqrt{20}-3\right)^2}}}\)

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

\(=\sqrt{5-\sqrt{6-\sqrt{20}}}\)

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

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

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

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

c)\(\left(\sqrt{3}-\sqrt{2}\right)\sqrt{5+2\sqrt{6}}\)

\(=\left(\sqrt{3}-\sqrt{2}\right)\sqrt{3+2\cdot\sqrt{3}\cdot\sqrt{2}+2}\)

\(=\left(\sqrt{3}-\sqrt{2}\right)\sqrt{\left(\sqrt{3}+\sqrt{2}\right)^2}\)

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

\(=3-2=1\)

d)\(\sqrt{5-\sqrt{13+4\sqrt{3}}}+\sqrt{3+\sqrt{13+4\sqrt{3}}}\)

\(=\sqrt{5-\sqrt{12+2\cdot\sqrt{12}+1}}+\sqrt{3+\sqrt{12+2\cdot\sqrt{12}+1}}\)

\(=\sqrt{5-\sqrt{\left(\sqrt{12}+1\right)^2}}+\sqrt{3+\sqrt{\left(\sqrt{12}+1\right)^2}}\)

\(=\sqrt{5-\sqrt{12}-1}+\sqrt{3+\sqrt{12}+1}\)

\(=\sqrt{4-\sqrt{12}}+\sqrt{4+\sqrt{12}}\)

\(=\sqrt{3-2\sqrt{3}+1}+\sqrt{4+2\sqrt{3}+1}\)

\(=\sqrt{\left(\sqrt{3}-1\right)^2}+\sqrt{\left(\sqrt{3}+1\right)^2}\)

\(=\sqrt{3}-1+\sqrt{3+1}\)

\(=2\sqrt{3}\)

 

 

 

 

14 tháng 11 2018

Đề không khó, mỗi tội dài

14 tháng 11 2018

vậy thì bn làm hộ mik vs , mik cần gấp

7 tháng 11 2017

a) \(3\sqrt{3}-3\sqrt{4^2\cdot3}+2\sqrt{6^2\cdot3}-\left(2-\sqrt{3}\right)\)

\(3\sqrt{3}-3\cdot4\sqrt{3}+2\cdot6\sqrt{3}-2+\sqrt{3}\)

\(3\sqrt{3}-12\sqrt{3}+12\sqrt{3}-2+\sqrt{3}\)

\(4\sqrt{3}-2\)

b) \(3\sqrt{2}\left(\sqrt{5^2\cdot2}-2\sqrt{3^2\cdot2}+\sqrt{7^2\cdot2}\right)\)

\(3\sqrt{2}\left(5\sqrt{2}-6\sqrt{2}+7\sqrt{2}\right)\)

\(3\sqrt{2}\left(6\sqrt{2}\right)\) \(=36\)

7 tháng 11 2017

\(a=\sqrt{27}-3\sqrt{48}+2\sqrt{108}-\sqrt{\left(2-\sqrt{3}\right)^2}\)

\(a=3\sqrt{3}-3\sqrt{48}+\sqrt{216}-2+\sqrt{3}\)

\(a=3\sqrt{3}-3\sqrt{48}+3\sqrt{24}-2+\sqrt{3}\)

\(a=3\left(\sqrt{3}-\sqrt{48}+\sqrt{24}+1\right)-2\)

Tính cái trong ngoặc là \(ok\).Em lười đi lấy máy tính lắm

\(b=3\sqrt{2}\left(\sqrt{50}-2\sqrt{18}+\sqrt{98}\right)\)

\(b=3\sqrt{100}-3\sqrt{72}+3\sqrt{196}\)

\(b=3\left(\sqrt{100}-\sqrt{72}+\sqrt{196}\right)\)(Tính trong ngoặc)

a) \(\sqrt{18}\)-2\(\sqrt{50}\)+\(\sqrt{\left(2-\sqrt{2}\right)^2}\)

=3\(\sqrt{2}\)-10\(\sqrt{2}\)+(2-\(\sqrt{2}\))2

= 3\(\sqrt{2}\)-10\(\sqrt{2}\)+4-2

= -7\(\sqrt{2}\)+2

29 tháng 9 2017

a) \(\sqrt{18}-2\sqrt{50}+\sqrt{\left(2-\sqrt{2}\right)^2}\)

=\(3\sqrt{2}-10\sqrt{2}+2-\sqrt{2}=2-8\sqrt{2}\)

b)\(\sqrt{\dfrac{1}{3}}+\dfrac{3}{\sqrt{3}}+\dfrac{1}{2-\sqrt{3}}\)

=\(\dfrac{1}{3}\sqrt{3}+\sqrt{3}+\dfrac{1}{2-\sqrt{3}}=\dfrac{4}{3}\sqrt{3}+\dfrac{1}{2-\sqrt{3}}\)

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

c)\(\left(1+\sqrt{2}+\sqrt{3}\right)\left(1+\sqrt{2}-\sqrt{3}\right)\)

=\(\left(1+\sqrt{2}\right)^2-3=1+2\sqrt{2}+2-3=2\sqrt{2}\)

d)\(3\sqrt{200}-2\sqrt{0,08}-4\sqrt{\dfrac{9}{8}}\)

=\(30\sqrt{2}-0,4\sqrt{2}-3\sqrt{2}=26.6\sqrt{2}\)

1 tháng 7 2017

a,\(\sqrt{13+30\sqrt{2+\sqrt{9+4\sqrt{2}}}}\)

\(=\sqrt{13+30\sqrt{3+2\sqrt{2}}}\\ =\sqrt{13+30\left(\sqrt{2}+1\right)}\)

\(=\sqrt{43+30\sqrt{2}}=5+3\sqrt{2}\)

1 tháng 7 2017

b, \(\sqrt{5-\sqrt{13+4\sqrt{3}}}+\sqrt{3+\sqrt{13+4\sqrt{3}}}\)

\(\Leftrightarrow\sqrt{5-\sqrt{\left(2\sqrt{3}\right)^2+2.2\sqrt{3}+1}}+\sqrt{3+\sqrt{\left(2\sqrt{3}\right)^2+2.2\sqrt{3}+1}}\)

\(\Leftrightarrow\sqrt{5-\sqrt{\left(2\sqrt{3}+1\right)^2}}+\sqrt{3+\sqrt{\left(2\sqrt{3}+1\right)^2}}\)

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

\(\Leftrightarrow\sqrt{\left(\sqrt{3}-1\right)^2}+\sqrt{\left(\sqrt{3}+1\right)^2}\)

\(\Leftrightarrow\sqrt{3}-1+\sqrt{3}+1\)

\(\Leftrightarrow2\sqrt{3}\)