\(\dfrac{-8^3\cdot6^4}{18^{12}}=\dfrac{2^3\cdot4^3\cdot2^2\cdot3^2}{2^{12}\cdot3^{12}\cdot3^{12}}\)

\(=\dfrac{2^5\cdot\left(2^2\right)^3\cdot3^2}{2^{12}\cdot3^{12}\cdot3^{12}}=\dfrac{2^6}{2^7\cdot3^{10}\cdot3^{12}}\)

\(=\dfrac{1}{2\cdot3^{22}}\)

\(\frac{9^9\cdot225^5\cdot8^7}{18^{12}\cdot625^3\cdot24^3}=\frac{9^9\cdot\left(\left(3\cdot5\right)^2\right)^5\cdot8^7}{\left(9\cdot2\right)^{12}\cdot\left(\left(5^2\right)^2\right)^3\cdot\left(8\cdot3\right)^3}\)

\(=\frac{1}{9^3\cdot2^{12}}\cdot\frac{9^5\cdot5^{10}}{5^{12}}\cdot\frac{8^7}{8^3\cdot3^3}\)

\(=\frac{9^2\cdot8^4}{2^{12}\cdot5^2\cdot3^3}\)

\(=\frac{9\cdot\left(2^4\right)^3}{\left(2^4\right)^3\cdot5^2}\)

\(=\frac{9}{25}\)

c

C

\(C.\dfrac{2}{3}\)

a 6/10 = 3/5 

3/5 < 4/5

b 6/12 = 1/2

3/4 > 1/2

6/10=3/5=0,6;4/5=0,8=0,6<0,8

là 20/50 đó mk chăcs thế mk đầu tien k cho mk nhé

8/2:4  9/3:3   36/18:2

duyệt đi

\(\frac{8}{2}\)=4                      \(\frac{9}{3}\)=3                 \(\frac{36}{18}\)=2
 

8/2=8:2=4

9/3=9:3=3

36/18=36:18=2

mấy bạn chú ý nha,khi tử số chia hết cho mẫu số thì ta chia luôn,không cần rút gọn nữa

3 phan 2

12 phan 4 bang 3

9 phan 7

tk nha

\(\frac{9}{6}=\frac{9\div3}{6\div3}=\frac{3}{2}\)

\(\frac{12}{4}=\frac{12:4}{4:4}=\frac{3}{1}=3\)

\(\frac{90}{70}=\frac{90:10}{70:10}=\frac{9}{7}\)

rút gọn bằng cách chia nha

k mik nha bn

9 phần 6 = 3 phan 2

12 phần 4 =3

90 phần 70= 9 phần 7

tk cho minh nha 

chuc ban hoc gioi