Đề bài

Rút gọn mỗi biểu thức sau: a) \(\frac{{{a^{\frac{7}{3}}} - {a^{\frac{1}{3}}}}}{{{a^{\frac{4}{3}}} - {a^{\frac{1}{3}}}}} \,\,\,(a > 0;a \ne 1)\). b) \(\sqrt [3] {\sqrt {{a^{12}b^{6}}}}\,\,\,(a > 0;b > 0)\).

Lời giải chi tiết

🥃a) $\frac{{{a}^{\frac{7}{3}}}-{{a}^{\frac{1}{3}}}}{{{a}^{\frac{4}{3}}}-{{a}^{\frac{1}{3}}}}=\frac{{{a}^{\frac{1}{3}}}\left( {{a}^{2}}-1 \right)}{{{a}^{\frac{1}{3}}}\left( a-1 \right)}=\frac{\left( a-1 \right)\left( a+1 \right)}{\left( a-1 \right)}=a+1$.

ܫb) \(\sqrt[3]{\sqrt{{{a}^{12}}{{b}^{6}}}}=\sqrt[3]{{{a}^{\frac{12}{2}}}.{{b}^{\frac{6}{2}}}}=\sqrt[3]{{{a}^{6}}.{{b}^{3}}}={{a}^{\frac{6}{3}}}{{b}^{\frac{3}{3}}}={{a}^{2}}b\).