So sánh \(7\sqrt[3]{8}\) và \(8\sqrt[3]{7}\)
Ta thấy \(7\sqrt[3]{8}=\sqrt[3]{7^3.8}=\sqrt[3]{2744}\)
\(8\sqrt[3]{7}=\sqrt[3]{8^3.7}=\sqrt[3]{3584}\)
Vậy nên \(7\sqrt[3]{8}\) < \(8\sqrt[3]{7}\)
Tìm x: \(\sqrt[3]{3x+3}+2=5\)
\(\sqrt[3]{3x+3}+2=5\)
\(\Leftrightarrow\sqrt[3]{3x+3}=3\)
\(\Leftrightarrow3x+3=27\)
\(\Leftrightarrow3x=24\Leftrightarrow x=8.\)
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