Tìm x: A) – 5(x+1/5)-1/2(x-2/3)=3/2x-5/6 B) 3(x-1/2)-5(x+3/5)=-x+1/5 Ai làm nhanh mk vote 5star.

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1. Đáp án: A)x=1/42

                 B)x=-27/10

   Giải thích các bước giải:

   A) – 5(x+1/5)-1/2(x-2/3)=3/2x-5/6

        -5x+(-5).1/5-1/2x-1/2.2/3-3/2x=-5/6

        x(-5.1/2.3/2)+(-5).1/5-1/2.2/3=-5/6

        -7x+-2/3=-5/6

        -7x=-1/6

           x=1/42

   B) 3(x-1/2)-5(x+3/5)=-x+1/5

       3x-3.1/2-5x+5.3/5+x=1/5

        x(3-5+1)-3.1/2+5.3/5=1/5

         -1x-5/2=1/5

         -1x=27/10

            x=-27/10

    

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2. *Lời giải :

   `a) -5 (x + 1/5) – 1/2 (x – 2/3) = 3/2x – 5/6`

   `⇔ -5x -1 – 1/2x + 1/6 = 3/2x – 5/6`

   `⇔ (-5x – 1/2x) + (-1 + 1/6) = 3/2x – 5/6`

   `⇔ (-11)/2x – 5/6 = 3/2x – 5/6`

   `⇔ (-11)/2x  – 3/2x = 5/6 – 5/6`

   `⇔ -7x = 0`

   `⇔ x = 0`

   Vậy `x= 0`

   `b) 3 (x – 1/2) – 5 (x + 3/5) = -x + 1/5`

   `⇔ 3x – 3/2 – 5x – 3 = -x + 1/5`

   `⇔ (3x – 5x) + (-3/2 – 3) = -x + 1/5`

   `⇔ -2x – 9/2 = -x + 1/5`

   `⇔ -2x + x = 9/2 + 1/5`

   `⇔ -x = 47/10`

   `⇔ x = -47/10`

   Vậy `x = -47/10`

    

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