Tìm x i) ( 2 x + 1 ) mũ 3 = 9 ⋅ 81 .
Giải thích
i) \[{\left( {2x + 1} \right)^3} = 9 \cdot 81\]
\[{\left( {2x + 1} \right)^3} = {9^3}\]
Suy ra \[2x + 1 = 9\]
\[2x = 9 - 1\]
\[2x = 8\]
\[x = 8:2\]
\[x = 4\]
Vậy \(x = 4\).
i) \[{\left( {2x + 1} \right)^3} = 9 \cdot 81\]
\[{\left( {2x + 1} \right)^3} = {9^3}\]
Suy ra \[2x + 1 = 9\]
\[2x = 9 - 1\]
\[2x = 8\]
\[x = 8:2\]
\[x = 4\]
Vậy \(x = 4\).