Question

tìm x,biết

5-x-16=40+x

4x-10=15-x

15-x=4x-5

x-15=6+4x

-12+x=5x-20

7x-4=20+3x

5x-7=-21-2x

x+15=20-4x

17-x=7-6x

Answer 1

5-x-16=40+x

-x-x=40+16-5

(-x).2=51

-x=51/2=>x=51/2

Answer 2

1.x=40

2.x=10

3.x=

Answer 3

15-x = 4x -5 

15 + 5 = 4x + x 

5x = 20

x= 4

x - 15 = 6 + 4x 

-15 - 6 = 4x -x 

3x = -21 

x= -7

Answer 4

-12 + x = 5x - 20

  x - 5x = -20 + 12

      -4x = -8

         x = -8 : (-4)

         x = 2

  7x - 4 = 20 + 3x

7x - 3x = 20 + 4

       4x = 24

         x = 24 : 4

         x = 6

Answer 5

5x - 7 = -21 - 2x 

5x + 2x = -21 +7

7x = -14 

x =-2

x + 15 = 20 - 4x 

x + 4x = 20 - 15

5x = 5

x=1 

17 - x = 7 - 6x 

-x + 6x = 7 - 17 

5x = -10

x = -2

Answer 6

5 - x - 16 = 40 + x

      -x - x = 40 - 5 + 16

         -2x = 51 

            x = 51 : (-2)

            x = \(\dfrac{-51}{2}\)

4x - 10 = 15 - x

 4x + x = 15 + 10 

       5x = 25 

         x = 25 : 5

         x = 5