`!`

\(a,\dfrac{8}{9}\times\dfrac{7}{5}-\dfrac{7}{9}\times\dfrac{2}{5}+\dfrac{2}{9}\\ =\dfrac{8}{9}\times\left(\dfrac{7}{5}-\dfrac{2}{5}\right)+\dfrac{2}{9}\\ =\dfrac{8}{9}\times\dfrac{5}{5}+\dfrac{2}{9}\\ =\dfrac{8}{9}+\dfrac{2}{9}\\ =\dfrac{10}{9}\)

\(b,\dfrac{5}{9}\times\dfrac{1}{4}+\dfrac{4}{9}\times\dfrac{3}{12}\\ =\dfrac{5}{9}\times\dfrac{1}{4}+\dfrac{4}{9}\times\dfrac{1}{4}\\ =\dfrac{1}{4}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)\\ =\dfrac{1}{4}\times\dfrac{9}{9}\\ =\dfrac{1}{4}\)

a) 9 x 5 + 9 = 45 + 9     b) 9 x 2 + 9 = 18 + 9

   = 54     = 27

c) 9 x 7 + 9 = 63 + 9     d) 9 x 6 + 9 = 54 + 9

   = 70     = 63

B= {[ 5 * (2^2)^15 * (3^2)^9 ] - [ (2^2) * 3^20 * (2^3)^9 ]} / {[ 5 * (2^9) * (2^19)*(3^19) ] - [ 7 * (2^29) * (3^3)^6 ]} 
B= {[ 5 * (2^30) * (3^18) ] - [ (3^20) * (2^29) ]} / {[ 5 * (2^28) * (3^19) ] - [ 7 * (2^29) * (3^18) ]} 
B= {[ (2^29) * (3^18) ] * [(5 * 2) - 3^2 ]} / {[ (2^28) * (3^18) ] - [(5 * 3) - (7 * 2)] } 
B= [ (2^29) * (3^18) ] / [ (2^28) * (3^18) ] 
B= [ (2^1) * (2^28) * (3^18) ] / [ (2^28) * (3^18) ] 
B = 2

dấu * là dấu nhân

B= {[ 5 * (2^2)^15 * (3^2)^9 ] - [ (2^2) * 3^20 * (2^3)^9 ]} / {[ 5 * (2^9) * (2^19)*(3^19) ] - [ 7 * (2^29) * (3^3)^6 ]} 
B= {[ 5 * (2^30) * (3^18) ] - [ (3^20) * (2^29) ]} / {[ 5 * (2^28) * (3^19) ] - [ 7 * (2^29) * (3^18) ]} 
B= {[ (2^29) * (3^18) ] * [(5 * 2) - 3^2 ]} / {[ (2^28) * (3^18) ] - [(5 * 3) - (7 * 2)] } 
B= [ (2^29) * (3^18) ] / [ (2^28) * (3^18) ] 
B= [ (2^1) * (2^28) * (3^18) ] / [ (2^28) * (3^18) ] 
B = 2

dấu * là dấu nhân

Ta có:

a) ( 45 – 5 x 9 ) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= (45 – 45) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0 x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0

b) (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 8 x 8 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 64 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x 0

= 0

c) (36 – 4 x 9) : (3 x 5 x 7 x 9 x 11)

= (36 – 36) : (3 x 5 x 7 x 9 x 11)

= 0 : (3 x 5 x 7 x 9 x 11)

= 0

d) (27 – 3 x 9) : 9 x 1 x 3 x 5 x 7

= (27 – 27) : 9 x 1 x 3 x 5 x 7

= 0 : 9 x 1 x 3 x 5 x 7

=0

a) ( 45 – 5 x 9 ) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0 x 1 x 2 x 3 x 4 x 5 x 6 x 7

b) (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 8 x 8 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x 0

c) (36 – 4 x 9) : (3 x 5 x 7 x 9 x 11)

= 0 : (3 x 5 x 7 x 9 x 11)

d) (27 – 3 x 9) : 9 x 1 x 3 x 5 x 7

= 0 : 9 x 1 x 3 x 5 x 7                                                                                                                  Nếu đúng thì k cho mình nhé bạn!

a. ( 45 – 5 x 9 ) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= (45 – 45) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0 x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0

b. (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 8 x 8 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 64 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x 0

= 0

c. (36 – 4 x 9) : (3 x 5 x 7 x 9 x 11)

= (36 – 36) : (3 x 5 x 7 x 9 x 11)

= 0 : (3 x 5 x 7 x 9 x 11)

= 0

d. (27 – 3 x 9) : 9 x 1 x 3 x 5 x 7

= (27 – 27) : 9 x 1 x 3 x 5 x 7

= 0 : 9 x 1 x 3 x 5 x 7

=0

ban biet lam thi giai ra cho minh di

1, =4/9 x (3/7 + 2 x 4/7) - 1/9 - 3/9

= 4/9 x 1 - 1/9 - 3/9 = 0

2, = ( 22/5 x 5/22 ) x 12

= 1 x 12 = 12

thằng duc bị ngu à 

dễ còn hơn cả ăn bánh

\(\text{a)}\dfrac{-3}{5}-x=\dfrac{21}{10}\)

             \(x=\dfrac{-3}{5}-\dfrac{21}{10}=\dfrac{-27}{10}\)

\(\text{b)}x:\dfrac{2}{9}=\dfrac{9}{2}\)

   \(x\)        \(=\dfrac{9}{2}.\dfrac{2}{9}=1\)

\(\text{c) }\dfrac{x}{9}=\dfrac{5}{3}\)

\(\Rightarrow x=\dfrac{9.5}{3}=15\)

\(\text{d)}x:\left(\dfrac{2}{5}\right)^3=\left(\dfrac{5}{2}\right)^3\)

   \(x:\dfrac{8}{125}=\dfrac{125}{8}\)

   \(x\)           \(=\dfrac{125}{8}.\dfrac{8}{125}=1\)

a)2/9-(-4/9)=6/9=2/3

b)(-1/24+0,25+1 1/12):(-1/2)2

=(-1/24+6/24+26/24):(-1/2).2

=31/24.-2.2

=-31/12.2

=-31/6

c)3/13.(-5/9)+10/13.(-5/9)+(-4/9)

=-5/9(3/13+10/13)+(-4/9)

=-5/9.1+(-4/9)

=-1

1.

a)2/9-(-4/9)=6/9 

b)(-1/24+0,25+11/12):(-1/2)2

=1,125:-1

=-1,125

c) 3/13.-5/9+10/13.-5/9+-4/9

=-5/9.(3/13+10/13)+4/9

=5/9.1+4/9

=5/9+4/9

=9/9=1

2.

a)-41/5:x=51/4

           x=51/41.-41/5

           x=-1

    vậy x=-1                                    

b)7/12-5/12.x=1/12

          5/12.x=1/12+7/12

          5/12.x=6/12

                 x=6/12:5/12

                 x=6/12.12/5

                 x=6/5

  vậy x=6/5

`A=2/(1xx3)+2/(3xx5)+2/(5xx7)+2/(7xx9)+2/(9xx11)+2/(11xx13)`

`=1/1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13`

`=1/1-1/13`

`=13/13-1/13`

`=12/13`

3^x=3^2x3^2

3^x=3^4

Suy ra x =4

Giải 1 phần thui mệt was

a) 3^x = 3² . 9

3^x = 3² . 3²

3^x = 3⁴

=> x = 4

b) ( 21 + x ) : 9 = 9⁵ : 9⁴

(21 + x ) : 9 = 9

21 + x  = 9 . 9

21 + x = 81

x = 81 - 21

x = 60

c) 5^x + 1 - 13 = 613

5^x = 613 + 13 - 1

5^x = 625

5^x = 5⁴

=> x = 4

a)\(3^x=3^{^{ }}^2.9\)

\(3^x=3^2.3^2\)

\(3^x=3^{2+2}=3^4\)

\(\Rightarrow x=4\)

b)\(\left(21+x_{ }\right):9=9^5:9^4\)

\(\left(21+x\right):9=9^{5-4}=9\)

\(21+x=9.9\)

\(x=81-21=60\)

c)\(5^x-1-13=613\)

\(5^x-\left(1+13\right)=613\)

\(5^x=613+14=625\)

\(5x=5^4\)

\(\Rightarrow x=4\)

a= 9

b=45

A=9

B=45