=28,8x(71,2+28,2)x134x(1,1-0,1-1)
= ...........................x134x0
=..............x0
=0 

134 x 4 x 5

= 134 x (4 x 5)

= 134 x 20 = 1680

`136 -4^2 : x=134`

`=> 136-16:x=134`

`=> 16:x= 136-134`

`=> 16:x=2`

`=>x=16:2`

`=>x=8`

__

`19-5(x-1)=4`

`=> 5(x-1)=19-4`

`=> 5(x-1) =15`

`=> x-1=15:5`

`=>x-1=3`

`=>x=3+1`

`=>x=4`

__

`257-(x^2-1) =177`

`=>x^2-1=257-177`

`=>x^2-1=80`

`=>x^2=80+1`

`=>x^2=81`

`=>x^2=(+- 9)^2`

`=> x= +- 9`

__

`(x^2-17) : 8=2^3`

`=> x^2 -17 = 8 * 8`

`=> x^2 -17= 64`

`=> x^2 =64+17`

`=>x^2=81`

`=>x^2=(+- 9)^2`

`=> x= +- 9`

136 - 4² : x = 134

4² : x = 136 - 134

8 : x = 2

x = 8 : 2

x = 4

--------

129 - 5(x - 1) = 4

5(x - 1) = 129 - 4

5(x - 1) = 125

x - 1 = 125 : 5

x - 1 = 25

x = 25 + 1

x = 26

------------

257 - (x² - 1) = 177

x² - 1 = 257 - 177

x² - 1 = 80

x² = 80 + 1

x² = 81

x = -9 hoặc x = 9

--------

(x² - 17) : 8 = 8

x² - 17 = 8 . 8

x² - 17 = 64

x² = 64 + 17

x² = 81

x = -9 hoặc x = 9

a)-12+(x-9)=0

(x-9) = 12

x = 21

b) 13-(x-5)=8

(x-5) = -5

x = 0

c)134-5(x+4)=34

(x + 4 ) = 20

x = 16

d)4-(27-3)=x-(13-4)

-20 = x - 9

x = -11

134 - 5. ( x + 4 ) = 34

        5 . ( x + 4 ) = 134 - 34

        5 . ( x + 4 ) = 100

             ( x + 4 ) = 100: 5

             ( x + 4 ) = 20

               x        = 20 - 4

               x        = 16

134 - 5(x+4) = 34 

=> 134 - 5x - 20 = 34 

=> 114 - 5x = 34 

=> 5x = 114 - 34 

=> 5x = 80

=> x= 16

5(x+4) = 134-34

5(x+4) = 100

(x+4)   = 100 : 5

x+4    = 20

x       = 20-4

x      = 16

1) x = 4/5 - 1/3

x = 7/15

2) 5/3.x=1/21

x=1/35

3) -12/13.x = 1/13

x=-1/12

7) th1: x-1=2/3

x = 5/3

Th2: x - 1 = -2/3

x=1/3

ta co : 134-5*(x+4)=2^2*2^4

suy ra : 134-5x-20= 2^6

          134-64-20=5x

           50=5x

suy ra x=10