A.12 h 6x = 0 B.- 2x + 14 =0 C.3x + 1 = 7x – 11 D.2x + x + 12 = 0 E.x – 5 = 3 – x F.7 – 3x = 9 – x G.5 – 3x = 6x + 7 H.11 – 2x = x – 1 I.15 – 8x = 9 –

A.12 -6x = 0

⇔ 6x = 12

⇔ x = 2

 Vậy x= 2

B.- 2x + 14 =0

⇔ -2x = -14

⇔ x = 7

 Vậy x= 7

C.3x + 1 = 7x – 11

⇔ 3x -7x = -11 -1

⇔ -4x = -12

⇔ x = 3

  Vậy x= 3

D.2x + x + 12 = 0

⇔ 3x = -12

⇔ x = -4

  Vậy x= -4

E.x – 5 = 3 – x

⇔ x +x= 3 +5

⇔ 2x = 8

⇔ x = 4

 Vậy x= 4

F.7 – 3x = 9 – x

⇔ -3x +x = 9 -7

⇔ -2x = 2

⇔ x = -1

  Vậy x= -1

G.5 – 3x = 6x + 7

⇔ -3x -6x = 7 -5

⇔ -9x = 2

⇔ x = -2/9

Vậy x= -2/9

H.11 – 2x = x – 1

⇔ -2x -x = -1 -11

⇔ -3x = -12

⇔ x = 4

 Vậy x= 4

I.15 – 8x = 9 – 5x

⇔ -8x +5x = 9 -15

⇔ -3x = 6

⇔ x = -2

K.3 + 2x + 5 + 2x

⇔ 4x = -5 -3

⇔ 4x = -8

⇔ x = -2

 

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