a) -2/3 – 1/3 * 2x – 5 =3/2 b) 1/4*x+3/4=1/12

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1. Đáp án:

   a) -2/3 – 1/3 * 2x – 5 =3/2

   =>-1/3 * 2x=-2/3-3/2+5

   =>-1/3 * 2x=-20/30-45/30+150/30

   =>-1/3 * 2x=85/30

   =>2x=85/30:(-1/3)

   =>2x=85/30 x (-3)

   =>x=8,5 x 1/2

   =>x=85/20

   Vậy x=85/20

   b) 1/4*x+3/4=1/12

    1/4 * x =1/12-9/12

   1/4 *x=-8/12=-2/3

   x=-2/3:1/4

   x=-2/3 x 4

   x=-8/3

   Vậy x=-8/3

   Giải thích các bước giải:

   a) -2/3 – 1/3 * 2x – 5 =3/2

   =>-1/3 * 2x=-2/3-3/2+5

   =>-1/3 * 2x=-20/30-45/30+150/30

   =>-1/3 * 2x=85/30

   =>2x=85/30:(-1/3)

   =>2x=85/30 x (-3)

   =>x=8,5 x 1/2

   =>x=85/20

   Vậy x=85/20

   b) 1/4*x+3/4=1/12

    1/4 * x =1/12-9/12

   1/4 *x=-8/12=-2/3

   x=-2/3:1/4

   x=-2/3 x 4

   x=-8/3

   Vậy x=-8/3

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2. Giải thích các bước giải:

   `a)`
   `-2/3-1/3 . 2x-5=3/2`
   `=>(-2/3-5)-1/3. 2x=3/2`
   `=>(-2/3-15/3)-1/3 .2x=3/2`
   `=>-17/3 – 1/3 . 2x=3/2`
   `=>1/3 . 2x=-17/3-3/2`
   `=>1/3 . 2x=-34/6-9/6`
   `=>1/3 . 2x=-43/6`
   `=>2x=-43/6:1/3`
   `=>2x=-43/6 . 3`
   `=>2x=-43/2`
   `=>x=-43/2:2`
   `=>x=-43/2 . 1/2`
   `=>x=-43/4`
   Vậy `x=-43/4`
   `b)`
   `1/4 . x +3/4=1/12`
   `=>1/4 . x=1/12-3/4`
   `=>1/4 . x =1/12-9/12`
   `=>1/4 . x=-8/12`
   `=>x=-8/12:1/4`
   `=>x=-8/12 . 4`
   `=>x=-8/3`
   Vậy `x=-8/3`

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