70 – 5.(x – 3) = 45

5.(x -3) = 70 - 45

5.(x – 3) = 25

x – 3 = 25 : 5

x – 3 = 5

x = 5 + 3

x = 8

Vậy x = 8

70-5.(x-3)=45

=> 5.(x-3)=70-45

=> 5.(x-3)=25

=> x-3=25:5

=> x-3=5

=> x=5+3

Vậy x=8.

5.(x-3)=70-45=25

   x-3=25:5=5

   x   =5+3=8

Vậy x= 8

70-5.(x-3)=45
5.(x-3)=70-45
5.(x-3)=25
   x-3=25:5
x-3=5
x=3+5
x=8

a,  70 - 5 ( x - 3 ) = 45

⇔ 5 . x - 3 = 70 - 45

⇔ 5 x - 3 = 35

⇔ x - 3 = 35 : 5 ⇔ x - 3 = 7

⇔ x = 10

b,  10 + 2 x = 4 5 : 4 3

⇔ 10 + 2 x = 4 2 ⇔ 10 + 2 x = 16

⇔ 2 x = 4 ⇔ x = 2

c,  60 - 3 x - 2 = 51

⇔ 3 x - 2 = 60 - 51

⇔ 3 x - 2 = 9

⇔ x - 2 = 3 ⇔ x = 5

d,  4 x - 20 = 2 5 : 2 3

⇔ 4 x - 20 = 2 2 ⇔ 4 x - 20 = 4

⇔ 4 x = 24 ⇔ x = 6

\(70-5.\left(x-3\right)=45\)

\(5.\left(x-3\right)=70-45\)

\(5.\left(x-3\right)=25\)

\(x-3=25:5\)

\(x-3=5\)

         \(x=5+3\)

         \(x=8\)

70-5.(x-3)=45

5.(x-3)=35

x-3=7

->x=10

a) \(70-\left(x-3\right)=45\)

\(x-3=70-45\)

\(x-3=25\)

\(x=25+3\)

\(x=28\)

b) \(12+\left(5+x\right)=20\)

\(5+x=20-12\)

\(5+x=8\)

\(x=8-5\)

\(x=3\)

c) \(130-\left(100+x\right)=25\)

\(100+x=130-25\)

\(100+x=105\)

\(x=105-100\)

\(x=5\)

d) \(175+\left(30-x\right)=200\)

\(30-x=200-175\)

\(30-x=25\)

\(x=30-25\)

\(x=5\)

e) \(\left(x+12\right)+22=92\)

\(x+12=92-22\)

\(x+12=70\)

\(x=70-12\)

\(x=58\)

f) \(95-\left(x+2\right)=45\)

\(x+2=95-45\)

\(x+2=50\)

\(x=50-2\)

\(x=48\)

a)

70 - (x - 3) = 45

x - 3 = 70 - 45 = 25

x = 25 + 3 = 28

Vậy x = 28

b)

12 + (5 + x) = 20

5 + x = 20 - 12 = 8

x = 8 - 5 = 3

Vậy x = 3

c)

130 - (100 + x) = 25

100 + x = 130 - 25 = 115

x = 115 - 100 = 15

Vậy x = 15

d)

175 + (30 - x) = 200

30 - x = 200 - 175 = 25

x = 30 - 25 = 5

Vậy x = 5

e)

(x + 12) + 22 = 92

x + 12 = 92 - 22 = 70

x = 70 - 12 = 58

Vậy x = 58

f)

95 - (x + 2) = 45

x + 2 = 95 - 45 = 50

x = 50 - 2 = 48

Vậy x = 48

a 8406-3*x=1200
           3*x=8406-1200=7206
               x=7206:3
               x=2402
KL
b  70-5*(x-3)=45
         5*(x-3)=70-45=25
             x-3=25:5=5
             x   =5+3
             x=8
KL
Thêm dấu Suy ra nữa 
Hoa Minh ko có việc j làm à tick Thủy cái nha Minh Hoa
 

a) (2006+6400)-3*x=1200

8406-3*x=1200

3*x= 8406 - 1200

3*x= 7206

x = 7206:3

x= 2402

b)

70-5*(x-3)=45

5*(x-3)= 70-45

5*(x-3)=25

x-3=25:5

x-3=5

x=5+3

x=8

a)70-5.(x-3)=45

       5.(x-3)=70-45

       5.(x-3)=25

          (x-3)=25:5

          (x-3)=5

            x   =5+3

            x    =8

a) 70 - 5 . (x - 3) = 45

= 70 - 5 . 3 - x = 45

= 70 - 65 - x = 45

= 15 - x = 45

x = 15 - 45

x = -30

b) x - (2x - 4) = 0

= x - (20.x - 4) = 0

= 0 + 4 + 20 = x

=> x = 0 + 4 + 20

x = 24

Đs:

Chả biết đúng hay không nữa

70 - 5(x-3) = 45

=> 5(x-3) = 25

=> x - 3 = 5

x = 8

10 + 2x = 4⁵ : 4³ = 16

=> 2x = 6

x = 3