a) 3/14 x – 1/4 = 2(x – 3) + 1/4 x b) 30\%x-x+ 5 6 = 1 3 cần gấp nhé ????

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1. a) `3/14 x – 1/4 = 2(x-3) + 1/4x`

   `=> 3/14 x – 1/4 = 2x -6 + 1/4x`

   `=> 3/14 x – 2x – 1/4 x = -6 + 1/4`

   `=> (3/14 -2-1/4) x = -23/4`

   `=>-57/28 x = -23/4`

   `=> x= (-23/4) : (-57/28)`

   `=> x= -23/4 . (-28/57)`

   `=> x= 161/57`

   Vậy `x= 161/57`

   b) `30% x – x +5/6 = 1/3`

   `=> 3/10 x – x = 1/3 – 5/6`

   `=> (3/10 -1) x = -1/2`

   `=> -7/10 x = -1/2`

   `=> x= -1/2 : (-7/10)`

   `=> x= -1/2 . (-10/7)`

   `=> x=5/7`

   Vậy `x= 5/7`

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2. `a//`

   `3/14x – 1/4 = 2(x-3) + 1/4x`

   `⇒ 3/14x – 1/4 = 9/4x – 6`

   `⇒ 3/14x = -23/4 + 9/4x`

   `⇒ -57/28x = -23/4`

   `⇒ -57x = -161`

   `⇒ x = 161/57`

   Vậy `x = 161/57`

   `b//`

   `30%x – x + 56 = 13`

   `⇒ 3/10x – x + 56 = 13`

   `⇒ 3/10x – x = -43`

   `⇒ -7x = -430`

   `⇒ x = 430/7`

   Vậy `x = 430/7`

    

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