a) 120 - 20 : x = 110

20:x= 120 - 110

20:x= 10

x= 20:10=2

b) 213 - ( x - 13 ) = 1442 : 14

213 - (x-13)=103

x-13= 213 - 103

x-13=110

x=110+13

x=123

c) 2550 : [ 120 - ( x - 5 ) ] = 25

120 - (x-5) = 2550:25

120 - (x-5)=102

x-5 = 120 - 102

x-5= 18

x=18+5

x=23

a,120-20:X=110

20:X=120-110

20:X=10

     X=20:10

     X=2

 b, 213-[X-13]=1442:14

213-[x-13]=103

        x-13=213-103

         x-13=110

          x=110+13

           x=123

c,2550:[120-{x-5}]=25

120-{x-5}=2550:25

120-x-5=102

       x-5=120-102

       x-5=18

        x=18+5

         x=23

a) x = 44.             

b) x = 40.            

c) x = 95.             

d) x = 10.

a) x - 120: 30 = 40

    x    -40        =40

              x        =40+40

              x        =80

b) (x + 120) : 20 = 8

    (x+ 120)         = 8x20

     x+120           =160

     x                   = 160-120

     x                  = 40

c) (x + 5). 3 = 300

     x+5=300:3

     x+5=100

     x=100-5

     x=95

d) x.2 + 21 : 3= 27

    x.2   +7=27

      x.2   = 27-7

    x.2= 20

      x=20:2

      x=10

\(x\in BC\left(20;120;56\right)\)

\(\Leftrightarrow x=840\)

a. 20 + 8.(x + 3) = 5² . 4

8.(x + 3)             = 100 - 20

x + 3                  = 80 : 8

x                        = 10 - 3

x                        = 7

b. 120 + |x| = 150

|x|               = 150 - 120

|x|               = 30

x                 = + 30

a) 20 + 8(x + 3) = 5² . 4

 20 + 8(x + 3) = 100

8(X + 3) = 100 - 20

8(x + 3) = 80

x + 3 = 80 : 8

 x + 3 = 10

x = 10 - 3

x = 7

b) 120 + |x| = 150

|x| = 150 - 120

|x| = 30

=> \(\orbr{\begin{cases}x=30\\x=-30\end{cases}}\)

\(a,20+8.\left(x+3\right)=5^2.4\)

\(\Rightarrow20+8.\left(x+3\right)=25.4\)

\(\Rightarrow20+8.\left(x+3\right)=100\)

\(\Rightarrow8.\left(x+3\right)=100-20\)

\(\Rightarrow8.\left(x+3\right)=80\)

\(\Rightarrow x+3=80:8\)

\(\Rightarrow x+3=10\)

\(\Rightarrow x=10-3\)

\(\Rightarrow x=7\)

\(b,120+|x|=150\)

\(\Rightarrow|x|=150-120\)

\(\Rightarrow|x|=30\)

\(\Rightarrow x=\pm30\)

Lớp 6 rồi mà gà quá :v

Ta có:

10+20+30=(120:(x-6)+24)

=>(120:(x-6)+24)=60

=> 120:(x-6)=36

=> x-6=10/3

=> x=28/3

Ta có :

10 + 20 = 30 = [ 120 : ( x - 6 ) + 24 ]

Suy ra [ 120 : ( x - 6 ) + 24 ] = 60

Suy ra 120 : ( x - 6 ) = 36

Suy ra x - 6 = 10/3

Suy ra x = 28/3

10 + 20 + 30 = (120 : (x - 6) + 24)

60 = (120 : (x - 6) + 24)

=> (120 : (x - 6) + 24) = 60 

120 : x - 6 = 60 - 24 

120 : x - 6 = 36 

x - 6 = 120 : 36 

x - 6 = \(\frac{10}{3}\)

x = \(\frac{10}{3}+6\)

x = \(\frac{10}{3}+\frac{6}{1}=\frac{10}{3}+\frac{18}{3}\)

=> x = \(\frac{28}{3}\)

a) x = 34             

b) x= 5                

c) x = 35              

d) x = 0

e) x = 410            

f) x= 170

`@` `\text {Ans}`

`\downarrow`

`a,`

`(x-1954) \times 5=50`

`x-1954 = 50 \div 5`

`x-1954 = 10`

`x=10 + 1954`

`x= 1964`

`B.`

`48 - 40 \times x=8`

`40 \times x=48-8`

`40 \times x = 40`

` x=40 \div 40`

`x=1`

`C.`

`2+70 \div x = 3`

`70 \div x = 3-2`

`70 \div x = 1`

`x=70 \div 1`

`x=70`

`D. [3 \times (x+2) \div 7]  \times  4=120`

`3 \times (x+2) \div 7 = 120 \div 4`

`3 \times (x+2) \div 7 =30`

`3 \times (x+2) = 30 \times 7`

`3 \times (x+2)=210`

`x+2=210 \div 3`

`x+2=70`

`x=70-2`

`x=68`

`E.`

`7,2 \div [ (0,6 \times x+8) \div 20 + 59] = 0,12?` Thiếu ngoặc bạn nhé._.

\(a,\left(x-1954\right)\times5=50\\ x-1954=50:5\\ x-1954=10\\ x=1954+10\\ x=1964\\b.48-40\times x=8\\40\times x=48-8\\40\times x=40\\ x=40:40\\ x=1 \\ c.2+70:X=3\\ 70:x=3-2\\ 70:x=1\\ x=70:1\\ x=70\\ d,\left[3\times\left(x+2\right):7\right]\times4=120\\ 3\times\left(x+2\right):7-120:4\\ 3\times\left(x+2\right):7=30\\ \left(x+2\right):7=30:3\\ \left(x+2\right):7=10\\ x+2=10\times7\\ x+2=70\\ x=70-2\\ x=68\)