Bài 1:

a: \(x=\dfrac{2}{3}:\dfrac{3}{5}=\dfrac{2}{3}\cdot\dfrac{5}{3}=\dfrac{10}{9}\)

b: \(x=\dfrac{17}{8}:\dfrac{7}{17}=\dfrac{17}{8}\cdot\dfrac{17}{7}=\dfrac{289}{56}\)

c: \(x=-\dfrac{3}{4}:\dfrac{7}{12}=\dfrac{-3}{4}\cdot\dfrac{12}{7}=\dfrac{-63}{28}=-\dfrac{9}{4}\)

d: \(\Leftrightarrow x\cdot\dfrac{1}{6}=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{1}{4}\)

hay \(x=\dfrac{1}{4}:\dfrac{1}{6}=\dfrac{3}{2}\)

e: \(\Leftrightarrow\dfrac{1}{2}:x=-4-\dfrac{1}{3}=-\dfrac{17}{3}\)

hay \(x=-\dfrac{1}{2}:\dfrac{17}{3}=\dfrac{-3}{34}\)

dad

***c,4(x-5)-3(x+7)=-19

Suy ra (4x-20)-(3x+21)=-19

Suy ra (4x-3x)-(20+21)=-19

Suy ra x-41=-19

suy ra x=-19+41

Suy ra x=22

Vậy x=22

c,4(x-5)-3(x+7)=-19 Suy ra (4x-20)-(3x+21)=-19 Suy ra (4x-3x)-(20+21)=-19 Suy ra x-41=-19 suy ra x=-19+41 Suy ra x=22 Vậy x=22

Giúp

Bài 1 : 

\(=\dfrac{2}{11}+\dfrac{4}{11}-\dfrac{6}{11}-\dfrac{3}{8}-\dfrac{5}{8}=0-1=-1\)

Bài 2 : 

\(\Rightarrow3+x=8\Leftrightarrow x=5\)

Bài 3 : 

\(\Leftrightarrow x-\dfrac{5}{11}=\dfrac{5}{4}\Leftrightarrow x=\dfrac{35}{44}\)

Bài 4 : 

Trong 2 ngày An đọc được số quyên phần quyên sách 

\(\dfrac{1}{11}+\dfrac{8}{11}=\dfrac{9}{11}\)( quyển sách ) 

đs : 9/11 quyển sách 

B

b

b

`x/8 = 3/4 +(-5/8)`

`=>x/8 = 6/8 +(-5/8)`

`=>x/8 = 1/8`

`=>x=1`

`-----`

`x/12 =3/4 +(-2/3)`

`=>x/12 = 9/12 + (-8/12)`

`=> x/12=1/12`

`=>x=1`

`----`

`1+11/13=24/x`

`=> 13/13 +11/13=24/x`

`=> 24/13 =24/x`

`=>x=13`

`----`

`x/6 -3/4=1/12`

`=>x/6 = 1/12 +3/4`

`=>x/6 = 1/12 + 9/12`

`=>x/6 = 10/12`

`=>x/6= 5/6`

`=>x=5`

\(a)\)

\(\dfrac{x}{8}=\dfrac{3}{4}+\dfrac{-5}{8}\)

\(\Rightarrow\dfrac{x}{8}=\dfrac{1}{8}\)

\(\Rightarrow x.8=1.8\)

\(\Rightarrow x.8=8\)

\(\Rightarrow x=8:8\)

\(\Rightarrow x=1\)

\(b)\)

\(\dfrac{x}{12}=\dfrac{3}{4}+\dfrac{-2}{3}\)

\(\Rightarrow\dfrac{x}{12}=\dfrac{1}{12}\)

\(\Rightarrow x.12=1.12\)

\(\Rightarrow x.12=12\)

\(\Rightarrow x=12:12\)

\(\Rightarrow x=1\)

\(c)\)

\(1+\dfrac{11}{13}=\dfrac{24}{x}\)

\(\Rightarrow\dfrac{24}{13}=\dfrac{24}{x}\)

\(\Rightarrow x.24=24.13\)

\(\Rightarrow x.24=312\)

\(\Rightarrow x=312:24\)

\(\Rightarrow x=13\)

\(d)\)

\(\dfrac{x}{6}-\dfrac{3}{4}=\dfrac{1}{12}\)

\(\Rightarrow\dfrac{x}{6}=\dfrac{1}{12}+\dfrac{3}{4}\)

\(\Rightarrow\dfrac{x}{6}=\dfrac{5}{6}\)

\(\Rightarrow x.6=5.6\)

\(\Rightarrow x.6=30\)

\(\Rightarrow x=30:6\)

\(\Rightarrow x=5\)

A) 1000000 - 107492 : 154 x 28 + 1000

= 1000000 - 19544 + 1000

= 981456

B) 8/15 + 4/7 + 14/30 + 12/21 + 5

= 15/7 + 5

= 50/7

C) 9/13 : 6/11 - 5/12 : 6/11

= 9/13 x 11/6 - 5/12 x 11/6

= (9/13 - 5/12) x 11/6

= 43/156 x 11/6

= 473/936

Bài 2

1) X x2 + X x 1/5 = 8/5 

X x (2 + 1/5 ) = 8/5

X x 11/5 = 8/5

X = 8/5 x 5/11

X = 8/11

2) X : 3/8 = 4/3 : 3/6 

X : 3/8 = 8/3

X = 8/3 x 3/8

X = 1

a) 1 000 000 - 107 492 : 154 x 28 + 1000

=  1 000 000 -            698     x 28 + 1000

=  1 000 000 -                    19544 + 1000

=                    980 456                 + 1000

=                                       981 456

b) 8/15 + 4/7 + 14/30 + 12/21 + 5

  = ( 8/15 + 14/30 ) + ( 4/7 + 12/21 ) + 5

  = ( 16/30 + 14/30 ) + ( 12/21 + 12/21 ) + 5

  =            30/30      +          24/21         + 5

  =               1          +         24/21          + 5

  =           ( 1 + 5 ) + 24/21

  =                6      + 24/21

  =                     150/21

 =                         50/7