a) 5/9 x 12/25 = 4/15

b) 12/11 : 36/55 = 5/3

c) 9/55 x 22 = 18/5

d) 144/7 : 36 = 4/7

a) 5/9 x 12/25 = 4/15

b) 12/11 : 36/55 = 5/3

c) 9/55 x 22 = 18/5

d) 144/7 : 36 = 4/7

a) 5/9 x 12/25 = 4/15

b) 12/11 : 36/55 = 5/3

c) 9/55 x 22 = 18/5

d) 144/7 : 36 = 4/7

a: 12/5:x=11/5

=>x=12/5:11/5=12/5*5/11=11/12

b: 5:x=9/3

=>5:x=3

=>x=5/3

12/5:x=11/5

       X=12/5:11/5

        X=12/11

5:x=9/3 

   X=5:9/3

   X=5/3

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

\(b)\frac{-11.13^7}{11^5.13^8}=\frac{-1}{11^4.13}\) (Bạn xem thử xem có sai đề không nhé)

\(c)\frac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}=\frac{2^{10}.3^9\left(3+1\right)}{2^9.3^{10}}=\frac{2.4}{3}=\frac{8}{3}\)

\(d)\frac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}+9.5^{11}.7^{11}}=\frac{5^{11}.7^{11}\left(7+1\right)}{5^{11}.7^{11}\left(5.4+9\right)}=\frac{8}{20+9}=\frac{8}{29}\)

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

\(b)\frac{\left(-11\right)\cdot13^7}{11^5\cdot13^8}=\frac{-1}{11^4\cdot13}=\frac{-1}{14641\cdot13}=\frac{-1}{190333}\)

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

b)-5/12 . 2/11+(-5/12) . 9/11+5/12

=(-5/12+5/12).(2/11+9/11)

=0.1=0

c)6/9/10+(2/5-1/10)

=69/10+3/10

=36/5

\(b)\)\(\frac{-5}{12}.\frac{2}{11}+\frac{-5}{12}.\frac{9}{11}+\frac{5}{12}\)

\(=\frac{-5}{12}.\frac{2}{11}+\frac{-5}{12}.\frac{9}{11}+\frac{5}{12}.1\)

\(=\frac{-5}{12}.\left(\frac{2}{11}+\frac{9}{11}+1\right)\)

\(=\frac{-5}{12}.2\)

\(=\frac{-5}{6}\)

\(c)\)\(6\frac{9}{10}+\left(\frac{2}{5}-\frac{1}{10}\right)\)

\(=6\frac{9}{10}+\frac{2}{5}-\frac{1}{10}\)

\(=\left(6\frac{9}{10}-\frac{1}{10}\right)+\frac{2}{5}\)

\(=6\frac{4}{5}+\frac{2}{5}\)

\(=6\frac{6}{5}=7\frac{1}{5}\)

Ta có : \(A-1=\frac{9^{11}+1}{9^{11}-7}-1=\frac{8}{9^{11}-7}\) ; \(B-1=\frac{9^{12}+3}{9^{12}-5}-1=\frac{8}{9^{12}-5}\)

Cần so sánh : \(9^{11}-7\) và \(9^{12}-5\)

Ta viết : \(9^{12}-5=9^{11}.9-5=9^{11}.\left(1+8\right)-5=\left(9^{11}-7\right)+\left(8.9^{11}+2\right)\)

Xét : \(\left(9^{12}-5\right)-\left(9^{11}-7\right)=\left(9^{11}-7\right)+\left(8.9^{11}+2\right)-\left(9^{11}-7\right)=8.9^{11}+2>0\)

\(\Rightarrow9^{12}-5>9^{11}-7\)

Do đó : \(B-1>A-1\Rightarrow B< A\)

5/9 x 12/25 = 4/15

12/11 : 36/ 55 = 5/3

9/55 x 22 = 18/5 

144/7 : 36 = 4/7

4 phần 15

5 phần 3

18 phần 5

4 phần 7

\(\frac{5}{9}x\frac{12}{25}=\frac{4}{15}\)

\(\frac{12}{11}:\frac{36}{55}=\frac{5}{3}\)

\(\frac{9}{55}x22=\frac{18}{5}\)

\(\frac{144}{7}:36=\frac{4}{7}\)

60/225

660/396

198/55

144/252 

k nha bn

a)4/33

b)5/3

c)18/5

d)4/7