1)Rút gọn:
a) \(\frac{9^{14}\times25^5\times8^7}{18^{12}\times625^3\times24^3}\)
b)\(\frac{71\times52+53}{530\times71-180}\)
2)CMR:
\(\frac{abab}{cdcd}=\frac{ababab}{cdcdcd}\)
3)Tính hợp lí:
\(A=\frac{1}{3}-\frac{3}{4}-\left(\frac{-3}{5}-\frac{1}{57}+\frac{1}{36}+\frac{-1}{15}\right)-\frac{2}{9}\)