=9.9+25.9+33.9.2

=9.(9+25+33+2)

=9.69

=...

a. `306xx 18-306 xx 8=306 xx (18-8) =306 xx 10=3060`

b. `9 xx 9+25xx9 +33 xx18`

`=9 xx9 + 25 xx 9 + 33 xx 2 xx 9`

`=9x (9+25+33xx2)`

`=9 xx (9+25+66)`

`=9 xx 100`

`=900`

a) \(306\cdot18-306\cdot8=306\cdot10=3060\)

b) \(9\cdot9+25\cdot9\cdot33\cdot18=9\cdot9\cdot\left(1+25\cdot33\cdot2\right)=81\cdot1651=133731\)

a. 

b. 

485 phút, 4 giờ 18 phút, 32/7, 7/24, 9/4, 10

a ) x - ( - 18 ) = -24

x + 18 = -24

x = -24 - 18

x = -6

b ) -x - 17 + 8 = 33 - 19

-x - 17 + 8 = 14

-x - 17 = 14 - 8

-x - 17 = 6

-x =  -( 6 + 17 )

-x = - 23

c ) 15 - ( -4 + 7 ) = x - 14

15 + 4 + 7 = x - 14

27 = x - 14 

x - 14 = 27

x = 27 + 14

x = 41

d ) 9 - 25 = ( 7 - x ) - ( 25 + 7 ) 

( 7 - x ) - 32 = -16

7 - x = -16 + 32 

-7 - x = -16

x = -7 - ( - 16)

x = -7 + 16

x = 9

a) 9/22 x 33/18 =3/4

b) 12/35 : 36/25 = 5/21

c) 19/17 : 76/51 =3/4

a) \(\frac{9}{22}\times\frac{33}{18}\)

\(=\frac{9}{22}\times\frac{11}{6}\)

\(=\frac{9\times11}{22\times6}=\frac{3}{4}\)

b) \(\frac{12}{35}:\frac{36}{25}=\frac{12}{35}\times\frac{25}{36}\)

                     \(=\frac{5}{21}\)

c) \(\frac{19}{17}:\frac{76}{51}=\frac{19}{17}\times\frac{51}{76}\)

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

\(a,\frac{9}{22}x\frac{33}{18}\)

\(=\frac{3.3.11.3}{11.2.3.3.2}\)

\(=\frac{3}{2.2}\)

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

\(b,\frac{12}{35}:\frac{36}{25}\)

\(=\frac{12}{35}.\frac{25}{36}\)

\(=\frac{12.25}{35.36}\)

\(=\frac{12.5.5}{5.7.12.3}\)

\(=\frac{5}{7.3}\)

\(=\frac{5}{21}\)

\(c,\frac{19}{17}:\frac{76}{51}\)

\(=\frac{19}{17}.\frac{51}{76}\)

\(=\frac{19.51}{17.76}\)

\(=\frac{19.17.3}{17.19.4}\)

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

a: \(=\dfrac{18}{51}\cdot\dfrac{34}{9}\cdot\dfrac{17}{18}=\dfrac{17}{51}\cdot\dfrac{34}{9}=\dfrac{1}{3}\cdot\dfrac{34}{9}=\dfrac{34}{27}\)

b: \(=\dfrac{21}{32}\cdot\dfrac{4}{7}\cdot25\cdot\dfrac{4}{5}=\dfrac{21}{7}\cdot\dfrac{4}{32}\cdot20=60\cdot\dfrac{1}{8}=\dfrac{15}{2}\)

Ta có \(\frac{9}{25}x+\frac{3}{5}.\frac{9}{25}x+\frac{3}{5}.18+\frac{9}{25}x+18=x\)

=> \(\frac{9}{25}x\left(1+\frac{3}{5}+1\right)+18\left(\frac{3}{5}+1\right)=x\)

=> \(\frac{117}{125}x+28,8=x\)

=> \(x-\frac{117}{125}x=28,8\)

=> \(\frac{8}{125}x=28,8\)

=> x = 450

Vậy x = 450

\(\frac{9}{25}x+\frac{3}{5}.\frac{9}{25}x+\frac{3}{5}.18+\frac{9}{25}x+18=x\)

\(x\left(\frac{9}{25}+\frac{9}{25}+\frac{9}{25}\right).\frac{3}{5}+\frac{3}{5}.18+18=x\)

\(x.\frac{3}{5}\left(\frac{27}{25}+18\right)+18=x\)

\(x.\frac{3}{5}\left(\frac{27}{25}+\frac{450}{25}\right)+18=x\)

\(x.\frac{3}{5}.\frac{477}{25}+18=x\)

\(x.\frac{1431}{125}+\frac{2250}{125}=x\)

\(x.\frac{3681}{125}=x\)

vậy chac tui làm sai rồi

\(\frac{22}{5}x\frac{25}{18}=\frac{550}{90}=\frac{55}{9}\)

\(\frac{9}{11}:2\frac{5}{2}x2\frac{3}{4}=\frac{9}{11}:\frac{9}{2}x\frac{11}{4}=\frac{9}{11}x\frac{2}{9}x\frac{11}{4}=\frac{1}{2}\)

\(10:\frac{35}{24}:\frac{36}{7}=10x\frac{24}{35}x\frac{7}{26}=\frac{10}{1}x\frac{24}{35}x\frac{7}{26}=\frac{24}{13}\)

   10,77 x 9,8 + 5,23 x 9,8 

= (10,77 + 5,23) x 9,8 = 16 x 9,8 = 156,8

1,26 x 3,6 : 0,28 - 6,2 = 4,536 : 0,28 - 6,2=

16,2 - 6,2 = 10

20/11 x 33/23 x 69/180 =

1/1 x 3/1 x 3/9 =

3/1 x 1/3 = 1

(Câu cuối trong fx không có phần gạch giữa {S} nên mình ghi tạm ngoài này nha bạn!)