rút gọn phân số a) ​​(-3) mũ 10 x 15 mũ 5 phần 25 mũ 3 x (-9)mũ 7 b)2 mũ 3 + 3 (1/9 )mũ 0 – (1/2) mũ 2 x 4

$a$) $\dfrac{(-3)^{10} . 15^5}{25^3 . (-9)^7}$

$= \dfrac{3^{10} . (3.5)^5}{(5^2)^3 . (-3^2)^7}$

$= \dfrac{3^{10} . 3^5 . 5^5}{5^6 . (-3)^{14}}$

$= \dfrac{3^{15} . 5^5}{5^6 . (-3)^{14}}$

$= \dfrac{3.1}{5.(-1)}$

$= \dfrac{-3}{5}$.

$b$) `2^3 + 3.(1/9)^0 – (1/2)^2 . 4`

`= 8 + 3.1 – 1/4 .4`

`= 8 + 3 – 1`

`= 10`.