4( 18- 5x) – 12( 3x – 7) = 15( 2x – 16) – 6(x+ 14) (2x +2)(x – 1) – (x + 2).(2x + 1) = 0

0 bình luận về “4( 18- 5x) – 12( 3x – 7) = 15( 2x – 16) – 6(x+ 14) (2x +2)(x – 1) – (x + 2).(2x + 1) = 0”

1. `4(18-5x)-12(3x-7) = 15(2x-16) – 6(x+14)`

   `⇔ -56x + 156 = 24x – 324`

   `⇔ -56x = 24x – 480`

   `⇔ -80x = -480`

   `⇔ x = 6`

   Vậy `S = {6}`

   `(2x+2)(x-1)-(x+2)(2x+1)=0`

   `⇔ 2x^2 – 2 – 2x^2 – 5x – 2 = 0`

   `⇔ -5x – 4 = 0`

   `⇔ -5x = 4`

   `⇔ x = -4/5`

   Vậy `S = {-4/5}`

    

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2. `4( 18- 5x) – 12( 3x – 7) = 15( 2x – 16) – 6(x+ 14)`

   `<=> 72-20x-36x+84=30x-240-6x-84`

   `<=>156-56x=24x-324`

   `<=>80x=480`

   `<=>x=6`

   vậy nghiệm của pt `x=6`

   `(2x +2)(x – 1) – (x + 2)(2x + 1) = 0`

   `<=>2x²-2x+2x-2-2x²-x-4x-2=0`

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

   `<=>-5x=4`

   `<=>x=-4/5`

   vậy nghiệm của pt `x=-4/5`

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