Tính:
Bài 5. Tính:
a)$ [(\frac{2}{5})^{6}\times (\frac{2}{5})^{5}]/(\frac{2}{5})^{9}$
b) $[(\frac{3}{7})^{8}/(\frac{3}{7})^{7}]\times (\frac{3}{7}$
c)$ [(\frac{2}{5})^{9}\times (\frac{2}{5})^{4}]/[(\frac{2}{5})^{7}\times (\frac{2}{5})^{3}]$
a)$ [(\frac{2}{5})^{6}\times (\frac{2}{5})^{5}]/(\frac{2}{5})^{9}=[(\frac{2}{5})^{11}]/(\frac{2}{5})^{9}=(\frac{2}{5})^{2}=\frac{4}{25}$
b) $[(\frac{3}{7})^{8}/(\frac{3}{7})^{7}]\times (\frac{3}{7})=\frac{3}{7}\times\frac{3}{7}=\frac{9}{49}$
c) $[(\frac{2}{5})^{9}\times (\frac{2}{5})^{4}]/[(\frac{2}{5})^{7}\times (\frac{2}{5})^{3}]=(\frac{2}{5})^{13}/(\frac{2}{5})^{10}=(\frac{2}{5})^{3}=\frac{8}{125}$
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