giúp mk với TÌM X: a, $\frac{1}{2}$ x -$\frac{1}{3}$ x -$\frac{1}{4}$ = $\frac{-1}{5}$ b, $\frac{-1}{2}$ – $\frac{1}{2}$ (1-$\frac{1}{2}$ x)= $\fra

0 bình luận về “giúp mk với TÌM X: a, $\frac{1}{2}$ x -$\frac{1}{3}$ x -$\frac{1}{4}$ = $\frac{-1}{5}$ b, $\frac{-1}{2}$ – $\frac{1}{2}$ (1-$\frac{1}{2}$ x)= $\fra”

1. `a) 1/2 x – 1/3 x – 1/4 = -1/5`

   `(1/2 – 1/3) x            = -1/5 + 1/4`

   `1/6 x                       = 1/20`

         `x                        = 1/20 : 1/6`

         `x                        = 3/10`

   `b) -1/2 – 1/2 ( 1- 1/2x) = -1/3`

                 `1/2 ( 1 – 1/2x) = -1/2 – (-1/3)`

                  `1/2 ( 1 – 1/2x) = -1/6`

                         `(1 – 1/2x)= -1/6 : 1/2`

                           `1 – 1/2x = -1/3`

                                 `1/2x = 1 – (-1/3)`

                                  `1/2x = 4/3`

                                       `x = 4/3 : 1/2`

                                      `x = 8/3` 

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2. `a)`

   `1/2x – 1/3x – 1/4 = -1/5`

   `=> 1/2x – 1/3x = -1/5 + 1/4`

   `=> x . (1/2 – 1/3) = 1/20`

   `=> x . 1/6 = 1/20`

   `=> x = 1/20 : 1/6`

   `=> x = 3/10`

   Vậy `x=3/10`

   `b)`

   `-1/2 – 1/2 (1 – 1/2x) = -1/3`

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

   `=> 1/2 (1-1/2x) = -1/6`

   `=> 1 – 1/2x = -1/6 : 1/2`

   `=> 1 – 1/2x = -1/3`

   `=> 1/2x = 1 + 1/3`

   `=> 1/2x = 4/3`

   `=> x = 4/3 : 1/2`

   `=> x = 8/3`

   Vậy `x = 8/3`

    

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