2010.2009=.........

........-2009.2009=..........

vay x=..........

\(257-\left(3x+25\right)=157\)

\(3x+25=257-157\)

\(3x+25=100\)

\(3x=75\)

\(x=25\)

vay \(x=25\)

\(x-140:35=270\)

\(x-4=270\)

\(x=274\)

vay \(x=274\)

\(23-\left(x:13\right)=18\)

\(\frac{x}{13}=5\)

\(\frac{x}{13}=\frac{65}{13}\)

\(\Rightarrow x=65\)

vay \(x=65\)

\(9\left(x+5\right)-13=671\)

\(9x+45=684\)

\(9x=639\)

\(x=71\)

vay \(x=71\)

\(9\left(4x\right)-13=24\)

\(36x=37\)

\(x=\frac{37}{36}\)

vay \(x=\frac{37}{36}\)

\(\left(x-5\right)-34:17=1\)

\(\left(x-5\right)-2=1\)

\(x-5=3\)

\(x=8\)

vay \(x=8\)

\(\left(2x-7\right).3=3\)

\(2x-7=1\)

\(2x=8\)

\(x=4\)

vay \(x=4\)

\(\left(3x-5\right):2=4.5\)

\(\left(3x-5\right):2=20\)

\(3x-5=10\)

\(3x=15\)

\(x=5\)

vay \(x=5\)

con lai lam tuong tu 

mk moi tay roi nen ban tu lam vay

bạn làm tiếp thì mk đánh 2 tích nữa 

cảm ơn bạn giúp mk 

a. 580:(x-24)=329-150.2

    580:(x-24)=329-300

    580:(x-24)=29

            x-24=580:29

            x-24=20

                x=20+24

                x=44

b.43-(24-x)=20

         24-x= 43-20

         24-x=23

              x=24-23

              x=1

c.5.(x-30)+25=100

   5.(x-30)      =100-25

   5.(x-30)      =75 

       x-30        =75:5 

       x-30        =15

           x         =15+30 

           x         =45

e.x-140:35=270

   x-4=270

       x=270+4

       x=274

Câu d hình như đề bài sai rồi bạn

Có ai biết không giúp tôi với nhé 

a) 0,5 + ( x - 15/2 ) : 1/2 = 9/2

<=>      (x - 15/2 ): 1/2   = 9/2 - 0,5

<=>      (x - 15/2)  : 1/2   = 4 

<=>        (x - 15/2)          = 4 . 1/2 

<=>        x - 15/2            = 2

<=>        x                     = 2 + 15/2 

<=>        x                     = 19/2  

b) 2012x - 2010x  = 2014 

( 2012 - 2010 ) .x  = 2014 

  2x                     = 2014 

   x                      = 2014 :2  

   x                      = 1007  

cảm ơn

tích mình với

ai tích mình

mình tích lại

thanks

35.(24−6.x)=0

24-6x= 0:35

24-6x=0

6x=24-0

6x=24

x=24:6=4

3.(x+7)−15=27

3(x+7)=27+15

3(x+7)=42

x+7=42:3

x+7=14

x=14-7=7

TK MIK NHA~~

35.(24 - 6.x)= 0

24-6.x=35: 0

24-6.x=0

-6.x=0-24

-6.x= -24

x=-24 : -6

x=4

vậy x=4

3.(x + 7) -15=27

3.(x+7)=27+15

3.(x+7)=42

x+7= 42:3

x+7=14

x=14-7

x=7

vậy x=7

a) 5.(x-20) = 35

(x-20) = 35:5

x-20 = 7

x = 27

b) (x+125) -301 = 56

x+125 -301 = 56

x - 176 = 56

x = 56 +176

x= 232

c) 215 + (x-21):2 = 235

(x-21):2 = 235 - 215

(x-21):2 = 20

x-21 = 20 .2

x-21 = 40

x = 61

d) (x:23 +45) .67 = 8911

(x:23 +45) = 8911 : 67

x:23+45 = 133

x:23 = 133-45

x:23 = 88

x = 88.23

x = 2024

a) 5.(x - 20) = 35

⇒ x - 20 = 35 : 5

⇒ x - 20 = 7

⇒ x = 7 + 20

⇒ x = 27

b) (x + 125) - 301 = 56

⇒ x + 125 = 56 + 301

⇒ x + 125 = 357

⇒ x = 357 - 125

⇒ x = 232

c) 215 + (x - 21) : 2 = 235

⇒ (x - 21) : 2 = 235 - 215

⇒ (x - 21) : 2 = 20

⇒ x - 21 = 20 x 2 

⇒ x - 21 = 40

⇒ x = 21 + 40

⇒ x = 61

d) (x : 23 + 45).67 = 8911

⇒ x : 23 + 45 = 8911 : 67

⇒ x : 23 + 45 = 133

⇒ x : 23 = 133 - 45

⇒ x : 23 = 88

⇒ x = 88 x 23

⇒ x = 2024

a) \(5.\left(x-20\right)=35\)

\(x-20=35:5\)

\(x-20=7\)

\(x=7+20\Rightarrow x=27\)

b) \(\left(x+125\right)-301=56\)

\(x+125=357\)

\(x=357-125\Rightarrow x=232\)

c) \(215+\left(x-21\right):2=235\)

\(\left(x-21\right):2=20\)

\(x-21=40\Rightarrow x=40+21\Rightarrow x=61\)

d) \(\left(x:23+45\right).67=8911\)

\(x:23+45=133\)

\(x:23=88\Rightarrow x=88.23\Rightarrow x=2024\)

Ta có \(\dfrac{2}{1\cdot5}+\dfrac{2}{5\cdot9}+\dfrac{2}{9\cdot13}+...+\dfrac{2}{x\left(x+4\right)}=\dfrac{56}{113}\)

\(\dfrac{1}{2}\left(\dfrac{4}{1\cdot5}+\dfrac{4}{5\cdot9}+\dfrac{4}{9\cdot13}+...+\dfrac{4}{x\left(x+4\right)}\right)=\dfrac{56}{113}\)

\(1-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{13}+...+\dfrac{1}{x}-\dfrac{1}{x+4}=\dfrac{56}{113}:\dfrac{1}{2}\)

\(1-\dfrac{1}{x+4}=\dfrac{112}{113}\)

\(\dfrac{1}{x+4}=1-\dfrac{112}{113}=\dfrac{1}{113}\)

x + 4 = 113 ⇒ x = 109

\(\dfrac{2}{1.5}+\dfrac{2}{5.9}+...+\dfrac{2}{x\left(x+4\right)}=\dfrac{56}{113}\)

Xét: \(A=\dfrac{2}{1.5}+\dfrac{2}{5.9}+...+\dfrac{2}{x\left(x+4\right)}\)

\(A=\dfrac{1}{2}.\left(1-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{9}+...+\dfrac{1}{x-4}-\dfrac{1}{x}+\dfrac{1}{x}-\dfrac{1}{x+4}\right)\)

\(A=\dfrac{1}{2}.\left(1-\dfrac{1}{x+4}\right)\)

Với \(A=\dfrac{56}{113}\) thì

 \(\dfrac{1}{2}.\left(1-\dfrac{1}{x+4}\right)=\dfrac{56}{113}\)

\(\left(1-\dfrac{1}{x+4}\right)=\dfrac{112}{113}\)

\(\dfrac{1}{x+4}=\dfrac{1}{113}\)

\(x=109\)

\(\dfrac{2}{1.5}\) + \(\dfrac{2}{5.9}\)  + \(\dfrac{2}{9.13}\)+...+  \(\dfrac{2}{x\left(x+4\right)}\)   = \(\dfrac{56}{113}\)

(\(\dfrac{2}{1.5}+\dfrac{2}{5.9}+\dfrac{2}{9.13}+....+\dfrac{2}{x\left(x+4\right)}\) ) \(\times\) 2  = \(\dfrac{56}{113}\) \(\times\) 2

\(\dfrac{4}{1.5}\) + \(\dfrac{4}{5.9}\) +\(\dfrac{4}{9.13}\)+...+ \(\dfrac{4}{x\left(x+4\right)}\)                = \(\dfrac{112}{113}\)

\(\dfrac{1}{1}\) - \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) - \(\dfrac{1}{9}\) + \(\dfrac{1}{9}\) - \(\dfrac{1}{13}\) +...+ \(\dfrac{1}{x}\) - \(\dfrac{1}{x+4}\) = \(\dfrac{112}{113}\)

1  - \(\dfrac{1}{x+4}\) = \(\dfrac{112}{113}\)

        \(\dfrac{1}{x+4}\) = 1 - \(\dfrac{112}{113}\)

        \(\dfrac{1}{x+4}\) = \(\dfrac{1}{113}\)

         \(x\) + 4 = 113

         \(x\)        = 113 - 4

         \(x\)        = 109

\(5\cdot x+10\cdot9=990\)

\(\Rightarrow5\cdot x+90=990\)

\(\Rightarrow5\cdot x=900\)

\(\Rightarrow x=\dfrac{900}{5}\)

\(\Rightarrow x=180\)

_____________

\(1045:\left[215-\left(3\cdot x-24\right)\right]=5\)

\(\Rightarrow215-\left(3\cdot x-24\right)=1045:5\)

\(\Rightarrow215-\left(3\cdot x-24\right)=209\)

\(\Rightarrow3\cdot x-24=215-209\)

\(\Rightarrow3\cdot x-24=6\)

\(\Rightarrow3\cdot x=30\)

\(\Rightarrow x=10\)

`@` `\text {Ans}`

`\downarrow`

`5.x + 10.9 = 990`

`\Rightarrow 5x + 90 = 990`

`\Rightarrow 5x = 990 - 90`

`\Rightarrow 5x = 900`

`\Rightarrow x = 900 \div 5`

`\Rightarrow x = 180`

Vậy, `x = 180`

\(1045 \div [ 215 - (3 . x - 24 ) ] = 5\)

`\Rightarrow 1045 \div (215 - 3x + 24) = 5`

`\Rightarrow 191 + 3x = 1045 \div 5`

`\Rightarrow 191 + 3x = 209`

`\Rightarrow 3x = 209 - 191`

`\Rightarrow 3x =18`

`\Rightarrow x = 18 \div 3`

`\Rightarrow x = 6`

Vậy, `x = 6.`

5x+10.9=990

=>5x+90=990

=>5x=990-90

=>5x=900

=>x=900:5

=>x=180

______________

1045:[215-(3x-24)]=5

=>215-(3x-24)=1045:5

=>215-(3x-24)=209

=>3x-24=215-209

=>3x-24=6

=>3x=6+24

=>3x=30

=>x=30:3

=>x=10