Bài làm

\(\frac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}\)

\(=\frac{2^{10}\left(3^{10}-3^9\right)}{2^9.3^{10}}\)

\(=\frac{2\left[3^9\left(3-1\right)\right]}{3^{10}}\)

\(=\frac{2\left[3^9.2\right]}{3^{10}}\)

\(=\frac{4.3^9}{3^{10}}\)

\(=\frac{4}{3}\)

Vậy giá tị biểu thức là \(\frac{4}{3}\)

4/3 nha bạn 

Hai câu a) và b) bạn chỉ cần xem số mũ rồi trừ số mũ là xong 

\(c)\) \(\frac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}=\frac{2^{10}.3^9\left(3-1\right)}{2^9.3^{10}}=\frac{2^{10}.3^9.2}{2^9.3^{10}}=\frac{2^{11}.3^9}{2^9.3^{10}}=\frac{2^2}{3}=\frac{4}{3}\)

\(d)\) \(\frac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}+9.5^{11}.7^{11}}=\frac{5^{11}.7^{11}\left(7+1\right)}{5^{11}.7^{11}\left(5.7+9\right)}=\frac{8}{35+9}=\frac{8}{44}=\frac{2}{11}\)

Chúc bạn học tốt 

Ta có : 21^0.3^10−2^10.3^9/2^9.3^10
=> 2^10.(3^10−3^9)/2^9.3^10
=> 2^10.3/2^9.3^10
=> 2/3^9=2/19683

dòng đầu tiên là 

ta có 2^10

nhé

thien ty tfboys ơi cách làm là gì

a/ = -5/9

b/ = 13

c/= 4/3

d/ =5/9

tích đi...^.^!!!

nhìu thế 

đăng từng câu một mới có cơ có người trả lời đó bạn 

minh cung dang hok lop?

\(\frac{2^{10}\cdot3^{10}-2^{10}\cdot3^9}{2^9\cdot3^{10}}\)\(=\frac{2^{10}\cdot3^9\left(3-1\right)}{2^9\cdot3^{10}}\)\(=\frac{2\cdot2}{3}=\frac{4}{3}\)

Vậy \(\frac{2^{10}\cdot3^{10}-2^{10}\cdot3^9}{2^9\cdot3^{10}}=\frac{3}{4}\)

a. \(\dfrac{3^{10}.\left(-5\right)^{21}}{\left(-5\right)^{20}.3^{12}}\) = \(\dfrac{3^{10}.\left(-5\right)^{20}.\left(-5\right)}{\left(-5\right)^{20}.3^{10}.3^2}\) = \(\dfrac{-5}{3^2}\)= \(\dfrac{-5}{9}\)

b. \(\dfrac{-11^5.13^7}{11^5.13^8}\) = \(\dfrac{-11^5.13^7}{11^5.13^7.13}\)= \(\dfrac{-1}{13}\)

c. \(\dfrac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}\)= \(\dfrac{2^{10}\left(3^{10}-3^9\right)}{2^9.3^{10}}\)= \(\dfrac{2^{10}.3}{2^9.3^{10}}\)= \(\dfrac{2^9.2.3}{2^9.3.3^9}\)= \(\dfrac{2}{3^9}\)=\(\dfrac{2}{19683}\)

a ) Tử số : 2^10 . 3^10 - 2^10 . 3^9 

      = 2^10 . 3^9 ( 3 - 1 ) 

      = 2^10 . 3^9 . 2  = 2^11 . 3^9

=> Phân số : 2^11  . 3^9 /2^9 . 3^10 = 4/3

b ) 5^12 . 7^12 + 9 . 5^11 . 7^11 

= 5^11 . 7^11 ( 5 . 7 + 9 ) 

=5^11 . 7^11 . 44

\(\left(-\right)\frac{1989\cdot1990+3970}{1992\cdot1991+3984}=\frac{1989\cdot\left(1990+2\right)}{1992\cdot\left(1991+2\right)}=\frac{1989}{1993}\)

\(\left(-\right)\frac{3^{10}\cdot\left(-5\right)^{21}}{\left(-5\right)^{20}\cdot3^{12}}=\frac{3^{10}\cdot\left(-5\right)^{20}\cdot\left(-5\right)}{3^{10}\cdot\left(-5\right)^{20}\cdot3^2}=-\frac{5}{9}\)

\(\left(-\right)\frac{\left(-11\right)^5\cdot13^7}{11^5\cdot13^8}=\frac{11^5\cdot13^7\cdot\left(-1\right)}{11^5\cdot13^7\cdot13}=-\frac{1}{13}\)

\(\left(-\right)\frac{2^{10}\cdot3^{10}-2^{10}\cdot3^9}{2^9\cdot3^{10}}=\frac{2^{10}\cdot3^9\left(3-1\right)}{2^9\cdot3^{10}}=\frac{2^{11}\cdot3^9}{2^9\cdot3^{10}}=\frac{4}{3}\)