tìm x biết a,-2/3.x=4/15 b,21/13.x=-7/26 c,-14/25.x=-42/35 d,22/15.x=-8/27

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1. `a,` `{-2}/3.x=4/15`

   `⇒x=4/15:{-2}/3`

   `⇒x=4/15. 3/{-2}`

   `⇒x={-8}/{45}`

   `b,` `21/13.x={-7}/26`

   `⇒x={-7}/26:21/13`

   `⇒x={-7}/26. 13/21`

   `⇒x={-1}/6`

   `c,` `{-14}/25.x={-42}/35`

   `⇒{-14}/25.x={-6}/5`

   `⇒x={-6}/5:{-14}/25`

   `⇒x={-6}/5. 25/{-14}`

   `⇒x=15/7`

   `d,` `22/15.x={-8}/27`

   `⇒x={-8}/27:22/15`

   `⇒x={-8}/27. 15/22`

   `⇒x={-20}/99`

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2. Đáp án:

    

   Giải thích các bước giải:

   a,-2/3.x=4/15

   x=4/15:(-2/3)

   x=-2/5

   Vậy x=-2/5

   b,21/13.x=-7/26

   x=(-7/26):21/13

   x=-1/6

   Vậy x=-1/6

   c,-14/25.x=-42/35

   x=-42/35:-14/25

   x=15/7

   Vậy x=15/7

   d,22/15.x=-8/27

   x=(-8/15):22/15

   x=-4/11

   Vậy x=-4/11

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