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11 tháng 6 2017

x = \(\sqrt{29+12\sqrt{5}}-\sqrt{29-12\sqrt{5}}\)

x = \(\sqrt{\left(2\sqrt{5}\right)^2+2.2\sqrt{5}.3+3^2}\) - \(\sqrt{\left(2\sqrt{5}\right)^2-2.2\sqrt{5}.3+3^2}\)

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

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

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

x = \(2\sqrt{5}+3-2\sqrt{5}+3\) = 6

11 tháng 6 2017

\(x=\sqrt{29+12\sqrt{5}}-\sqrt{29-12\sqrt{5}}\)

\(\Rightarrow x=\sqrt{\left(3+2\sqrt{5}\right)^2}-\sqrt{\left(3-2\sqrt{5}\right)^2}\)

\(\Rightarrow x=3+2\sqrt{5}-\left(2\sqrt{5}-3\right)\)

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

\(\Rightarrow x=6\)

22 tháng 9 2021

a) \(=\sqrt{\left(3\sqrt{5}-2\right)^2}+\sqrt{\left(3\sqrt{5}+2\right)^2}=3\sqrt{5}-2+3\sqrt{5}+2=6\sqrt{5}\)

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

22 tháng 9 2021

đầu tiên là bình phương hai vế ko âm ạ?

31 tháng 8 2021

\(a,\sqrt{29-12\sqrt{5}}=2\sqrt{5}-3\\ b,\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}}\\ =\sqrt{\sqrt{5}-\sqrt{3-2\sqrt{5}+3}}\\ =\sqrt{\sqrt{5}-\sqrt{6-2\sqrt{5}}}\\ =\sqrt{\sqrt{5}-\left(\sqrt{5}-1\right)}\\ =\sqrt{1}=1\)

a: \(\sqrt{29-12\sqrt{5}}=2\sqrt{5}-3\)

b: \(\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}}\)

\(=\sqrt{\sqrt{5}-\sqrt{6-2\sqrt{5}}}\)

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

=1

19 tháng 7 2017

\(=-10\)

\(=-6\)

22 tháng 8 2020

a) \(E=\sqrt{\left|12\sqrt{5}-29\right|}-\sqrt{12\sqrt{5}+29}\)

\(\Leftrightarrow E^2=\left|12\sqrt{5}-29\right|-12\sqrt{5}-29\)

\(\Leftrightarrow E^2=29-12\sqrt{5}-12\sqrt{5}-29\)

\(\Leftrightarrow E^2=-24\sqrt{5}\)

\(\Leftrightarrow E=-2\sqrt{6\sqrt{5}}\)

b) Đặt \(F=\sqrt{\left|40\sqrt{2}-57\right|}-\sqrt{40\sqrt{2}+57}\)

\(\Leftrightarrow F^2=\left|40\sqrt{2}-57\right|-40\sqrt{2}-57\)

\(\Leftrightarrow F^2=57-40\sqrt{2}-40\sqrt{2}-57\)

\(\Leftrightarrow F^2=-80\sqrt{2}\)

\(\Leftrightarrow F=-4\sqrt{5\sqrt{2}}\)

\(x=\sqrt{\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}}\)

\(=\sqrt{\sqrt{5}-\sqrt{6-2\sqrt{5}}}\)

=1

Thay x=1 vào B, ta được:

\(B=-\sqrt{1}\cdot\left(\sqrt{1}-1\right)=0\)

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

\(=\sqrt{5-\sqrt{6-2\sqrt{5}}}\)

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

22 tháng 7 2021

H=\(\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}\)

H=\(\sqrt{5}-\sqrt{3-\sqrt{20-12\sqrt{5}+9}}\)

H=\(\sqrt{5}-\sqrt{3-\sqrt{\left(2\sqrt{5}\right)^2-2.3.2\sqrt{5}+3^2}}\)

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

H=\(\sqrt{5}-\sqrt{3-\left|2\sqrt{5}-3\right|}\)

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

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

H=\(\sqrt{5}-\sqrt{6-2\sqrt{5}}\)

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

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

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

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

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

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

H=1

 

Ta có: \(H=\sqrt{5}-\sqrt{3-\sqrt{29-12\sqrt{5}}}\)

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

\(=\sqrt{5}-\sqrt{6-2\sqrt{5}}\)

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

=1

a: Sửa đề: \(A=\sqrt{\left(4-\sqrt{15}\right)^2}+\sqrt{15}\)

\(=4-\sqrt{15}+\sqrt{15}=4\)

b: \(A=2-\sqrt{3}+\sqrt{3}-1=1\)

c: \(C=3\sqrt{5}-2-3\sqrt{5}-2=-4\)

d: Sửa đề: \(D=\sqrt{29+12\sqrt{5}}-\sqrt{29-12\sqrt{5}}\)

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

=6

7 tháng 7 2023

a) \(A=\sqrt{\left(4-\sqrt{15}\right)^2}+\sqrt{15}\)

\(A=\left|4-\sqrt{15}\right|+\sqrt{15}\)

\(A=4-\sqrt{15}+\sqrt{15}\)

\(A=4\)

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

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

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

\(B=1\)

c) \(C=\sqrt{49-12\sqrt{5}}-\sqrt{49+12\sqrt{5}}\)

\(C=\sqrt{\left(3\sqrt{5}\right)^2-2\cdot3\sqrt{15}\cdot2+2^2}-\sqrt{\left(3\sqrt{5}\right)^2+2\cdot3\sqrt{5}\cdot2+2^2}\)

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

\(C=\left|3\sqrt{5}-2\right|-\left|3\sqrt{5}+2\right|\)

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

\(C=-4\)

d) \(D=\sqrt{29+12\sqrt{5}}-\sqrt{29-12\sqrt{5}}\)

\(D=\sqrt{\left(2\sqrt{5}\right)^2+2\cdot2\sqrt{5}\cdot3+3^2}-\sqrt{\left(2\sqrt{5}\right)^2-2\cdot2\sqrt{5}\cdot3+3^3}\)

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

\(D=\left|2\sqrt{5}+3\right|-\left|2\sqrt{5}-3\right|\)

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

\(D=6\)