Question

Answer 1

a.

<=> 4x - 8 > 5x + 5

<=> 4x - 8 - 5x - 5 > 0

<=> -x - 13 > 0

<=> -x > 13

=> x < -13

b.

<=> \(\dfrac{x+6}{12}-\dfrac{8}{12}< \dfrac{3x}{12}+\dfrac{2}{12}\)

<=> \(x+6-8< 3x+2\)

<=> x - 2 < 3x + 2

<=> x - 2 - 3x - 2 < 0

<=> -2x - 4 < 0

<=> -2x < 4

=> x > -2

Answer 2

c.

<=> \(\dfrac{2\left(x+6\right)}{6}-\dfrac{x-2}{6}< \dfrac{3\left(x+1\right)}{6}\)

<=> 2x + 12 - x + 2 < 3x + 3

<=> x + 14 < 3x + 3

<=> x + 14 - 3x - 3 < 0

<=> -2x + 11 < 0

<=> -2x < -11

<=> x > 11/2

d. e . và f bạn tự làm nha!

Answer 3

 

a)`4(x-2) > 5(x+1)`

`<=> 4x -8 > 5x +5`

`<=> 4x - 8 - 5x -5 >`0

`<=> -x - 13 >0`

`<=> -x > 13 => x < - 13`

Vậy `S={x|x<-13}`

b) \(\dfrac{x+6}{12}-\dfrac{2}{3}< \dfrac{x}{4}+\dfrac{1}{6}\)

`<=> `\(\dfrac{x+6-8}{12}< \dfrac{3x-2}{12}\)

`=> x - 2 < 3x+2`

`<=> x-3x < 2+2`

`<=>  -2x < 4`

`<=> x > -2`

Vậy `S={x|x>-2}`

c)\(\dfrac{x+6}{3}-\dfrac{x-2}{6}< \dfrac{x+1}{2}\)

`=> 2(x+6) - (x-2) < 3(x+1)`

`<=> 2x + 12 - x +2 < 3x+3`

`<=> x  + 14 - 3x -3 <0`

`<=> -2x < -11`

`=> x > 11/2 `

Vậy `S={x|x>11/2}`

d) `6x-5 >13`

`<=> 6x > 18`

`<=> x >3`

Vậy `S={x|x>3}`

Answer 4

x+612−812<3x12+212x+612−812<3x12+212

<=> $x+6-8<3x+2$

<=> x - 2 < 3x + 2

<=> x - 2 - 3x - 2 < 0

<=> -2x - 4 < 0

<=> -2x < 4

=> x > -2