Which expression is equivalent to \( 81^{\frac{1}{3}} \) ? \( 3 \sqrt[3]{3} \) \( 3 \sqrt{3^{3}} \) \( 9 \sqrt[3]{3} \) \( 27 \sqrt[3]{3} \)
Solución de tutoría real
Responder
Solución
Revisado y aprobado por el equipo de tutoría de UpStudy
Mind Expander
To find an expression equivalent to \( 81^{\frac{1}{3}} \), we can first rewrite 81 in terms of its prime factors: \( 81 = 3^4 \). So, we have: \[ 81^{\frac{1}{3}} = (3^4)^{\frac{1}{3}} = 3^{\frac{4}{3}} = 3^{1 + \frac{1}{3}} = 3 \cdot 3^{\frac{1}{3}} = 3 \sqrt[3]{3} \] Thus, the correct expression is \( 3 \sqrt[3]{3} \). To double-check, we can evaluate the given choices. \( 3 \sqrt{3^3} = 3 \cdot 3^{\frac{3}{2}} = 3^{1 + \frac{3}{2}} = 3^{\frac{5}{2}} \), which is not equal. \( 9 \sqrt[3]{3} = 3^2 \cdot 3^{\frac{1}{3}} = 3^{2 + \frac{1}{3}} = 3^{\frac{7}{3}} \), which is also not equal. Finally, \( 27 \sqrt[3]{3} = 3^3 \cdot 3^{\frac{1}{3}} = 3^{3 + \frac{1}{3}} = 3^{\frac{10}{3}} \), which is not equal either. Thus, the right answer is indeed \( 3 \sqrt[3]{3} \).