Tìm x : a/ 7/2 . ( x – 1 ) + 4/3 = 5/7 b/ 1/2 . ( x – 1/3 ) + 1/2 . (x + 2/3 ) = 1/4 c/ 4/3 . ( x – 1/2 ) = 1/2 . ( x + 1/3 ) d/ 3/4 . ( x

Bởi

Tìm x :
a/ 7/2 . ( x – 1 ) + 4/3 = 5/7
b/ 1/2 . ( x – 1/3 ) + 1/2 . (x + 2/3 ) = 1/4
c/ 4/3 . ( x – 1/2 ) = 1/2 . ( x + 1/3 )
d/ 3/4 . ( x + 1/2 ) -1/3 = 1/2 x

0 bình luận về “Tìm x : a/ 7/2 . ( x – 1 ) + 4/3 = 5/7 b/ 1/2 . ( x – 1/3 ) + 1/2 . (x + 2/3 ) = 1/4 c/ 4/3 . ( x – 1/2 ) = 1/2 . ( x + 1/3 ) d/ 3/4 . ( x”

  2. Đáp án:

     

    Giải thích các bước giải:

     a)  7/2 . ( x – 1 ) + 4/3 = 5/7

    ⇔ 7/2.(x-1)=5/7-4/3

          7/2.(x-1)=-13/21

               x-1=-13/21÷7/2

               x-1=-26/147

              x= -26/147+1

              x=-173/147

    b)    1/2 . ( x – 1/3 ) + 1/2 . (x + 2/3 ) = 1/4

    ⇔  1/2.x-1/6+1/2.x+1/3=1/4

      x=1/4-1/3+1/6

     x=1/12

    c)    4/3 . ( x – 1/2 ) = 1/2 . ( x + 1/3 )

           4/3.x-2/3=1/2.x+1/6

        4/3.x-1/2.x=1/6+2/3

            x.(4/3-1/2)=5/6

         x.5/6=5/6

      x=5/6÷5/6=1

    d)        3/4 . ( x + 1/2 ) -1/3 = 1/2 x

               3/4.x+3/8-1/3=1/2.x

              3/4.x-1/2.x=1/3-3/8

              1/4.x=-1/24

                 x=-1/24÷1/4=-1/6

        

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