Tính giá trị biểu thức:
Bài 7. Tính giá trị biểu thức:
a) $\frac{9^{3}\times 2^{10}}{16^{2}\times 81^{2}}$
b) $\frac{(-3)^{7}\times (-3)^{8}}{7 \times 9^{7}}$
c) $\frac{(0.3)^{6}\times (0.04)^{3}}{(0.09)^{4}\times (0.2)^{4}}$
d) $\frac{2^{3}+2^{4}+2^{5}+2^{6}}{15^{2}}$
a) $\frac{9^{3}\times 2^{10}}{16^{2}\times 81^{2}}=\frac{3^{6}\times 2^{10}}{2^{8}\times 3^{8}}=\frac{2^{2}}{3^{2}}=\frac{4}{9}$
b) $\frac{(-3)^{7}\times (-3)^{8}}{7 \times 9^{7}}=\frac{(-3)^{15}}{7 \times 9^{7}}=\frac{-3^{15}}{7 \times 3^{14}}=\frac{-3}{7}$
c) $\frac{(0.3)^{6}\times (0.04)^{3}}{(0.09)^{4}\times (0.2)^{4}}=\frac{(0.3)^{6}\times (0.2)^{6}}{(0.3^{8}\times (0.2)^{4}}=\frac{4}{9}$
d) $\frac{2^{3}+2^{4}+2^{5}+2^{6}}{15^{2}}=\frac{120}{15}=\frac{8}{15^{2}}$
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