\(\sqrt{81}làbaonhiêu\)
E2
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Kếtquảcủaphéptính 5 897 × 8 làbaonhiêu?
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\(\sqrt{\dfrac{4}{81}}:\sqrt{\dfrac{25}{81}}-1\dfrac{3}{5}\)
\(\sqrt{\dfrac{4}{81}}\div\sqrt{\dfrac{25}{81}}-1\dfrac{3}{5}=\dfrac{2}{9}\div\dfrac{5}{9}-\dfrac{8}{5}\)
\(=\dfrac{2}{5}-\dfrac{8}{5}=\dfrac{-6}{5}\)
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Nghiệm nhỏ nhất của phương trình:
giúp mik vs
\[ 5\sqrt{\frac{9x - 27}{25}} - 7\sqrt{\frac{4x - 12}{9}} - 7\sqrt{x^2 - 9} + 18\sqrt{\frac{9x^2 - 81}{81}} = 0 \]
=>\(5\cdot\dfrac{3\sqrt{x-3}}{5}-7\cdot\dfrac{2\sqrt{x-3}}{3}-7\cdot\sqrt{x^2-9}+18\cdot\sqrt{\dfrac{9}{81}\left(x^2-9\right)}=0\)
=>\(3\cdot\sqrt{x-3}-\dfrac{14}{3}\sqrt{x-3}=7\cdot\sqrt{x^2-9}-18\cdot\dfrac{3}{9}\cdot\sqrt{x^2-9}\)
=>\(-\dfrac{5}{3}\sqrt{x-3}=\sqrt{x^2-9}\)
=>\(\sqrt{x-3}\left(\sqrt{x+3}+\dfrac{5}{3}\right)=0\)
=>x-3=0
=>x=3
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So sánh \(\sqrt{\sqrt{81}}\)và \(\sqrt[4]{81}\)
Giai pt sau
\(25\sqrt{\dfrac{a-3}{25}}-7\sqrt{\dfrac{4a-12}{9}}-7\sqrt{a^2-9}+18\sqrt{\dfrac{9a^2-81}{81}}=0\)
Help me plsssss
=>\(25\cdot\dfrac{\sqrt{a-3}}{5}-7\cdot\dfrac{2}{3}\cdot\sqrt{a-3}-7\sqrt{a^2-9}+18\cdot\dfrac{1}{3}\sqrt{a^2-9}=0\)
=>\(\sqrt{a-3}\cdot\dfrac{1}{3}-\sqrt{a^2-9}=0\)
=>\(\sqrt{a-3}\left(\dfrac{1}{3}-\sqrt{a+3}\right)=0\)
=>a-3=0 hoặc a+3=1/9
=>a=3 hoặc a=-26/9
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\(\sqrt{81\cdot16\cdot169}\)= ?
\(\sqrt{10}\cdot\sqrt{810}=\)?
\(\sqrt{64}\cdot\sqrt{81\cdot100}-\sqrt{64}\cdot\sqrt{196\cdot16}\)=?
\(\sqrt{81.16.169}=\sqrt{81}.\sqrt{16}.\sqrt{169}=9.4.13=468\)
\(\sqrt{10}.\sqrt{810}=\sqrt{10.10}.\sqrt{81}=10.9=90\)
\(\sqrt{64}.\sqrt{81.100}-\sqrt{64}.\sqrt{196.16}=\sqrt{64}\left(\sqrt{81}.\sqrt{100}-\sqrt{196}.\sqrt{16}\right)=8.\left(9.10-14.4\right)=8.34=272\)
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\(25\sqrt{\dfrac{x-3}{25}}-7\sqrt{\dfrac{4x-12}{9}}-7\sqrt{x^2-9}+18\sqrt{\dfrac{9x^2-81}{81}}=0\)
Giải phương trình.
giúp e với ạaa :< gấp aa :((
\(25\sqrt{\dfrac{x-3}{25}}-7\sqrt{\dfrac{4x-12}{9}}-7\sqrt{x^2-9}+18\sqrt{\dfrac{9x^2-81}{81}}=0\left(x\ge3\right)\)
\(=25\sqrt{\dfrac{1}{25}.\left(x-3\right)}-7\sqrt{\dfrac{4}{9}.\left(x-3\right)}-7\sqrt{x^2-9}+18\sqrt{\dfrac{1}{9}.\left(x^2-9\right)}=0\)
\(=5\sqrt{x-3}-\dfrac{14}{3}\sqrt{x-3}-7\sqrt{x^2-9}+6\sqrt{x^2-9}=0\)
\(\Rightarrow\dfrac{1}{3}\sqrt{x-3}-\sqrt{\left(x-3\right)\left(x+3\right)}=0\Rightarrow\sqrt{x-3}-3\sqrt{\left(x-3\right)\left(x+3\right)}=0\)
\(\Rightarrow\sqrt{x-3}\left(1-3\sqrt{x+3}\right)=0\Rightarrow\left[{}\begin{matrix}\sqrt{x-3}=0\\1=3\sqrt{x+3}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{26}{9}\left(l\right)\end{matrix}\right.\)
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B 2. Thực hiện phép tính
a)\(\dfrac{\sqrt[3]{384}}{\sqrt[3]{3}}\)+\(3\sqrt[3]{-54}\)+\(\sqrt[3]{432}\) b)\(2\sqrt[3]{24}-5\sqrt[3]{81}+4\sqrt[3]{192}\)
c)\(\sqrt[3]{-343}.\sqrt[3]{3}+\sqrt[3]{81}-2\sqrt[3]{-24}\) d)\(8\sqrt[3]{5}-5\sqrt[3]{40}+10\sqrt[3]{\dfrac{1}{125}}\)
a: \(=4\sqrt[3]{2}-9\sqrt[3]{2}++6\sqrt[3]{2}=\sqrt[3]{2}\)
b: \(=6\sqrt[3]{3}-15\sqrt[3]{3}+16\sqrt[3]{3}=7\sqrt[3]{3}\)
c: \(=-7\sqrt[3]{3}+3\sqrt[3]{3}+6\sqrt[3]{3}=2\sqrt[3]{3}\)
d: \(=8\sqrt[3]{5}-10\sqrt[3]{5}+2=-2\sqrt[3]{5}+2\)
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