a: \(\dfrac{31995-81}{42660-108}=\dfrac{31914}{42552}=\dfrac{3}{4}\)

b: \(\dfrac{3\cdot5\cdot7\cdot11\cdot13\cdot37-10101}{1212120+40404}=\dfrac{545454}{1252524}=\dfrac{27}{62}\)

a, $\frac{31995-81}{42660-108}$

= $\frac{395.81-81}{395.108-108}$

=$\frac{81.394}{394.108}$

= $\frac{81}{108}$          = $\frac{3}{4}$

b, $\frac{3.5.7.11.13.37-10101}{1212120+40404}$

= $\frac{3.5.7.11.13.37-3.7.13.37}{\mathrm{3.7.12.13.37.10}+\mathrm{3.4.7.13.37}}$

= $\frac{\left(\mathrm{3.7.13.37}\right)(5.11-1)}{\left(\mathrm{3.7.13.37}\right)(120+4)}$

= $\frac{5.11-1}{120+4}$

= $\frac{54}{124}$ = $\frac{27}{62}$

ra số thập phân: 31886,99787

A = \(\frac{3^4\left(5.79-1\right)}{2^2.3^2\left(5.79-1\right)}=\frac{9}{4}\); B = \(\frac{3.7.13.37\left(5.11-1\right)}{4.3.7.13.37\left(3.5-1\right)}=\frac{54}{4.14}=\frac{2.9}{4.2.7}=\frac{9}{28}\)

Câu a)  \(\dfrac{31995-81}{42660-108}=\dfrac{31914}{42552}=\dfrac{31914:10638}{42552:10638}\)

             =\(\dfrac{3}{4}\)

Câu b) \(\dfrac{\left(3.5.7.11.13.15.37-10101\right)}{121212+40404}\)

          =\(\dfrac{\left(3.5.7.11.13.15.37-3.7.13.37\right)}{3.7.13.37.12+3.7.13.37.4}\)

          =\(\dfrac{3.7.13.37\left(5.11.15-1\right)}{3.7.13.37\left(12+4\right)}\)

          = \(\dfrac{824}{16}\)=\(\dfrac{103}{2}\)

?

a) \(\dfrac{31995-81}{42660-108}=\dfrac{31914}{42552}=\dfrac{3}{4}\)

b: \(\dfrac{3\cdot5\cdot7\cdot11\cdot37-10101}{1212120+40404}=\dfrac{32634}{1252524}=\dfrac{21}{806}\)

\(\frac{31995-81}{42660-108}=\frac{3}{4}\)

\(\frac{31995-81}{42660-108}\)

\(=\frac{31914}{42554}\)

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

Vậy ...........................................

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

A) 31995-81/ 42660- 108

= 31914/42552

= 3/4

B) 7.2.7.5²/ 14.2.5

= 14 . 7 . 25 / 140

= 98 . 25/140

= 2450/140

= 35/2

C) 2^2 . 3^3 . 5/ 3.2^3.5^3

= 4 . 27 . 5 / 3 . ( 2 . 5 )³

= 108 . 5 / 3. 10³

= 540 / 3000

= 9/50

f)\(\frac{15^2.16^4-15^3.16^3}{12^2.20^3-20^2+12^3}\)=\(\frac{15^2.16^3.\left(16-15\right)}{12^2.20^3.\left(20-12\right)}=\frac{15^2.16^3}{12^2.20^2.8}=\frac{1}{8}\)

\(A=\frac{4157-19}{12471-57}\)\(=\frac{4138}{12414}\)\(=\frac{4138:4138}{12414:4138}\)\(=\frac{1}{3}\)

\(B=\frac{7}{10^2+8.10^2}\)\(=\frac{7}{100+8.100}\)\(=\frac{7}{100+800}\)\(=\frac{7}{900}\)

\(C=\frac{31995}{42660-108}\)\(=\frac{31995}{42552}\)\(=\frac{31995:27}{42552:27}\)\(=\frac{1185}{1576}\)

\(D=\frac{2^{45}.5^3.2^6.3}{8.2^{18}.81.5}=\frac{2^{51}.5^3.3}{2^3.2^{18}.3^4.5}=\frac{2^{51}.5^3.3}{2^{21}.3^4.5}=\frac{2^{30}.5^2}{3^3}\)

k mình nhé.

A=4138/12414=1/3

B=7/900

C=31995/42552=1185/1576

Phần D tui chịu, ahihi

ko bt

\(\dfrac{18}{45}=\dfrac{2}{5}\dfrac{63}{81}=\dfrac{7}{9}\) minh chi co the lam the nay thoi vi minh dang co viec gap

a) 18/45=2/5

b)7/9

c)21/65

d)7/8

Theo thứ tự : 5/6 ; 2/3 ; 2/3 ; 3/2 ; 2/3 ; 3/8 ; 3/1(hay là 3)

\(\dfrac{10}{12}=\dfrac{5}{6}\)        \(\dfrac{8}{12}=\dfrac{2}{3}\)        \(\dfrac{10}{15}=\dfrac{2}{3}\)        \(\dfrac{27}{18}=\dfrac{3}{2}\)        \(\dfrac{24}{36}=\dfrac{4}{6}=\dfrac{2}{3}\)

\(\dfrac{18}{48}=\dfrac{3}{8}\)        \(\dfrac{42}{14}=\dfrac{6}{2}=\dfrac{3}{1}\)

10/12 = 5/6 

8/12 = 2/3 

10/15 = 2/3 

27/18 = 3/2 

18/48 = 3/8 

42/14 = 3