Lời giải:

a. 

$x-\frac{1}{2}=\frac{2}{3}$

$x=\frac{2}{3}+\frac{1}{2}=\frac{7}{6}$

b. 

$x\times \frac{5}{6}=\frac{1}{2}$
$x=\frac{1}{2}: \frac{5}{6}=\frac{3}{5}$

c.

$x:\frac{2}{5}=10$

$x=10\times \frac{2}{5}=4$

d.

$\frac{7}{5}-x=\frac{12}{10}$

$x=\frac{7}{5}-\frac{12}{10}=\frac{1}{5}$

`x+x:0,5+x:10=3,162`

`x+x xx2+x xx0,1=3,162`

`x xx(1+2+0,1)=3,162`

`x xx3,1=3,162`

`x=3,162:3,1`

`x=1,02`

_____________________________________

`2/5xx x+x xx1/5=2/7`

`x xx(2/5+1/5)=2/7`

`x xx3/5=2/7`

`x=2/7:3/5`

`x=10/21`

1) 2(x + 5) + 3(x + 7) = 41
2x + 10 + 3x + 21 = 41
5x + 31 = 41
5x = 10
x = 2
6) 7(x - 1) + 5(3 - x) = 11x - 10
7x - 7 + 15 - 5x = 11x - 10
2x + 8 = 11x - 10
-9x = -18
x = 2

2) 5(x + 6) + 2(x - 3) = 38
5x + 30 + 2x - 6 = 38
7x + 24 = 38
7x = 14
x = 2

7) 4(2 + x) + 3(x - 2) = 12
8 + 4x + 3x - 6 = 12
7x + 2 = 12
7x = 10
x = 10/7

3) 7(5 + x) + 2(x - 10) = 15
35 + 7x + 2x - 20 = 15
9x + 15 = 15
9x = 0
x = 0

8) 5(2 + x) + 4(3 - x) = 10x - 15
10 + 5x + 12 - 4x = 10x - 15
x + 22 = 10x - 15
9x = 37
x = 37/9

4) 3(x + 4) + (8 - 2x) = 22
3x + 12 + 8 - 2x = 22
x + 20 = 22
x = 2

9) 7(x - 2) + 5(3 - x) = 11x - 6
7x - 14 + 15 - 5x = 11x - 6
2x + 1 = 11x - 6
-9x = -7
x = 7/9

5) 4(x + 5) + 3(7 - x) = 49
4x + 20 + 21 - 3x = 49
x + 41 = 49
x = 8

10) 5(3 - x) + 5(x + 4) = 6 + 4x
15 - 5x + 5x + 20 = 6 + 4x
35 = 6 + 4x
4x = 29
x = 29/4

1) 2(x + 5) + 3(x + 7) = 41

2x + 10 + 3x + 21 = 41

5x + 31 = 41

5x = 41 - 31

5x = 10

x = 10 : 5

x = 2

2) 5(x + 6) + 2(x - 3) = 38

5x + 30 + 2x - 6 = 38

7x + 24 = 38

7x = 38 - 24

7x = 14

x = 14 : 7

x = 2

3) 7(5 + x) + 2(x - 10) = 15

35 + 7x + 2x - 20 = 15

9x + 15 = 15

9x = 15 - 15

9x = 0

x = 0

4) 3(x + 4) + (8 - 2x) = 22

3x + 12 + 8 - 2x = 22

x + 20 = 22

x = 22 - 20

x = 2

5) 4(x + 5) + 3(7 - x) = 49

4x + 20 + 21 - 3x = 49

x + 41 = 49

x = 49 - 41

x = 8

6) 7(x - 1) + 5(3 - x) = 11x - 10

7x - 7 + 15 - 5x = 11x - 10

2x - 11x + 8 = -10

-9x = -10 - 8

-9x = -18

x = -18 : (-9)

x = 2

7) 4(2 + x) + 3(x - 2) = 12

8 + 4x + 3x - 6 = 12

7x + 2 = 12

7x = 12 - 2

7x = 10

x = 10/7

8) 5(2 + x) + 4(3 - x) = 10x - 15

10 + 5x + 12 - 4x = 10x - 15

10x - 15 = x + 22

10x - x = 22 + 15

9x = 37

x = 37/9

9) 7(x - 2) + 5(3 - x) = 11x - 6

7x - 14 + 15 - 5x = 11x - 6

11x - 6 = 2x + 1

11x - 2x = 1 + 6

9x = 7

x = 7/9

10) 5(3 - x) + 5(x + 4) = 6 + 4x

15 - 5x + 5x + 20 = 6 + 4x

6 + 4x = 35

4x = 35 - 6

4x = 29

x = 29/4

a,

(2x-3)-(x-5)=(x+2)-(x-1)

2x-3-x+5=x+2-x+1

x+2=3

x=1

b,

2(x-1)-5(x+2)=-10

2x-2-5x+10=-10

-3x+8=-10

-3x=-18

x=6

a) ( 2x - 3 ) - ( x - 5 ) = ( x + 2 ) - ( x - 1 )

    2x - 3 - x + 5        = x + 2 - x + 1

    ( 2x - x ) + ( 5 - 3 ) = ( x - x ) + ( 2 + 1 )

    x + 2                    = 3

    x                          = 3 - 2

    x                          = 1

b) 2( x - 1 ) - 5( x + 2 ) = -10

    2x - 2.1 - 5x + 5.2   = -10

    2x - 2 - 5x + 10       = -10

    ( 2x - 5x ) + ( 10 - 2 ) = -10

    -3x + 8                    = -10

    -3x                          = -10 - 8

    -3x                          = -18

       x                         = -18 : -3

       x                         = 6

a: =>(x+10)(x-1)=0

=>x=-10 hoặc x=1

b: \(A=x^3-1-\left(x+5\right)\left(x^2-3\right)-5x^2-10x-5\)

\(=x^3-5x^2-10x-6-x^3+3x-5x^2+15\)

=-7x+9

=110/13

2(x – 1) – 5 (x + 2) = – 10

⇒ 2x – 2 – 5x – 10 = –10

⇒ -3x – 12 = – 10

⇒ – 3x = -10+12

⇒ -3x = 2

⇒ x = (-2)/3

Vậy : x = (-2)/3

\(\dfrac{x}{10}=\dfrac{1}{2}+\dfrac{2}{5}+\dfrac{3}{10}\)

\(\dfrac{x}{10}=\dfrac{5}{10}+\dfrac{4}{10}+\dfrac{3}{10}\)

\(\dfrac{x}{10}=\dfrac{12}{10}\)

\(=>x=12\)

=>x/10=5/10+4/10+3/10=12/10

=>x=12

\(\Rightarrow\cdot\dfrac{x}{10}=\dfrac{5}{10}+\dfrac{4}{10}+\dfrac{3}{10}=\dfrac{12}{10}\Rightarrow x=12\)

a) (2x -3) - (x- 5) = (x +2 ) - (x - 1)

( 2x - 3) - (x - 5) - (x + 2) + (x - 1) =0

     2x - 3 - x +5 - x - 2 + x - 1      =0

 (2x - x - x + x) + (-3 + 5 - 1)        = 0

           x          +       1               = 0

                     x                          = 0 - 1

                     x                          = -1 

b) 2(x - 1) - 5(x + 2) = -10

   2x - 2 - 5x + 10    = -10

  (2x - 5x) + (-2 + 10) = -10

  -3x + 8 = -10

  -3x = -10 - 8

  -3x = -18

    x = -18 : (-3)

    x = 6

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