\(=\sqrt{\left(2\sqrt{5}-7\right)^2}-\sqrt{\left(5-2\sqrt{5}\right)^2}\)
\(=7-2\sqrt{5}-5+2\sqrt{5}\)
\(=2\)
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Các câu hỏi tương tự
a, \(\sqrt{200}-\sqrt{32}+\sqrt{72}\)
b, \(4\sqrt{20}-3\sqrt{125}+5\sqrt{45}-15\sqrt{\dfrac{1}{5}}\)
c, \(\left(2\sqrt{8}+3\sqrt{5}-7\sqrt{2}\right)\left(72-5\sqrt{20}-2\sqrt{2}\right)\)
\(3\sqrt{20}-2\sqrt{45}+4\sqrt{5}.\)
\(\left(\sqrt{28}-2\sqrt{14}+\sqrt{7}\right)\sqrt{7}+7\sqrt{8}\)
\(3\sqrt{12}-4\sqrt{27}+5\sqrt{48}\)
\(\left(\sqrt{45}-2\sqrt{10}+\sqrt{5}\right)\sqrt{5}+5\sqrt{8}\)
Tính
(1) thực hiện phép tính:
a) \(\sqrt{5}.\left(\sqrt{20}-3\right)+\sqrt{45}\)
b) \(\sqrt{\left(5-\sqrt{3}\right)^2}-\sqrt{\left(2-\sqrt{3}\right)^2}\)
c) \(\dfrac{2}{\sqrt{5}+1}-\dfrac{2}{3-\sqrt{5}}\)
giúp mk vs ạ mai mk học rồi
b1,tínha,sqrt{left(sqrt{7}-4right)^2}+sqrt{8-2sqrt{7}}b,sqrt{left(sqrt{5}-2right)^2}+sqrt{6+2sqrt{5}}b2,rút gọn các biểu thức saua,5sqrt{dfrac{1}{5}}+dfrac{1}{2}sqrt{20}+sqrt{5}b,sqrt{dfrac{1}{2}}+sqrt{4,5}+sqrt{12,5}c,sqrt{20}-sqrt{45}+3sqrt{18}+sqrt{72}d,0,1timessqrt{200}+2timessqrt{0,08}+0,4timessqrt{50}
Đọc tiếp
b1,tính
a,\(\sqrt{\left(\sqrt{7}-4\right)^2}+\sqrt{8-2\sqrt{7}}\)
b,\(\sqrt{\left(\sqrt{5}-2\right)^2}+\sqrt{6+2\sqrt{5}}\)
b2,rút gọn các biểu thức sau
a,\(5\sqrt{\dfrac{1}{5}}+\dfrac{1}{2}\sqrt{20}+\sqrt{5}\)
b,\(\sqrt{\dfrac{1}{2}}+\sqrt{4,5}+\sqrt{12,5}\)
c,\(\sqrt{20}-\sqrt{45}+3\sqrt{18}+\sqrt{72}\)
d,\(0,1\times\sqrt{200}+2\times\sqrt{0,08}+0,4\times\sqrt{50}\)
LL
30 tháng 9 2021 lúc 22:08
* Tính
a. A=\(\left(\dfrac{6+\sqrt{20}}{3+\sqrt{5}}+\dfrac{\sqrt{14}-\sqrt{2}}{\sqrt{7}-1}\right):\left(2+\sqrt{2}\right)\)
b. B=\(\sqrt{5-2\sqrt{6}}+\sqrt{5+2\sqrt{6}}-\dfrac{11}{2\sqrt{3}+1}\)
\(3\sqrt{20}-2\sqrt{45}+4\sqrt{5}..\)
\(\left(\sqrt{28}-2\sqrt{14}+\sqrt{7}\right)\sqrt{7}+7\sqrt{8}\)
Tính
Giúp mình với mình cần gấp
Tính
A=\(\left(\frac{15}{\sqrt{7}+2}+\frac{12}{\sqrt{7}-1}-\frac{8}{3-\sqrt{7}}\right)\cdot\left(3\sqrt{7}+20\right)\)
B=\(\left(9+4\sqrt{5}\right):\left(\frac{\sqrt{5}+2}{\sqrt{5}-2}\right)\)
a. \(\sqrt{\left(2x+3\right)^2}=x+1\)
b. \(\sqrt{\left(2x-1\right)^2}=x+1\)
c. \(\sqrt{x+3}=5\)
d. \(\sqrt{x+2}=\sqrt{7}\)
e. \(5\sqrt{x}=20\)
f. \(\sqrt{x+4}=7\)
g. \(\sqrt{\left(2x+1\right)^2}=3\)
Tính:1) ( 2sqrt{5}-sqrt{7} ) left(2sqrt{5}+sqrt{7}right)2) left(5sqrt{2}+2sqrt{3}right)left(2sqrt{3}-5sqrt{2}right)3) sqrt{left(sqrt{7}-2right)^2}+sqrt{left(sqrt{7}+2right)^2}4) sqrt{left(sqrt{3}+sqrt{2}right)^2}+sqrt{left(sqrt{3}-sqrt{2}right)^2}5) left(sqrt{5}-sqrt{6}right)^26) left(sqrt{3}-sqrt{5}right)^27) left(2sqrt{2}+sqrt{3}right)^2
Đọc tiếp
Tính:
1) ( \(2\sqrt{5}-\sqrt{7}\) ) \(\left(2\sqrt{5}+\sqrt{7}\right)\)
2) \(\left(5\sqrt{2}+2\sqrt{3}\right)\left(2\sqrt{3}-5\sqrt{2}\right)\)
3) \(\sqrt{\left(\sqrt{7}-2\right)^2}+\sqrt{\left(\sqrt{7}+2\right)^2}\)
4) \(\sqrt{\left(\sqrt{3}+\sqrt{2}\right)^2}+\sqrt{\left(\sqrt{3}-\sqrt{2}\right)^2}\)
5) \(\left(\sqrt{5}-\sqrt{6}\right)^2\)
6) \(\left(\sqrt{3}-\sqrt{5}\right)^2\)
7) \(\left(2\sqrt{2}+\sqrt{3}\right)^2\)