7. Tìm x a) 2/3 . x = 2/7 b) x . 3/5 = 2/5 c) x : 8/13 = 13/7 d) 3/2 : x = 7/4

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1. `a ) 2/3 . x = 2/7 `

   `⇒ 2x = 2/7 . 3`

   `⇒ 2x = 6/7`

   `⇒ x = 3/7`

   `b ) x . 3/5 = 2/5`

   `⇒ 3x = 2/5 . 5`

   `⇒ 3x = 10/5`

   `⇒ x = 10/15 = 2/3`

   `c ) x : 8/13 = 13/7`

   `⇒ x/8 = 13 . 13/7`

   `⇒ x/8 = 169/7`

   `⇒ x = 8 . 169/7`

   `⇒ x = 1352/7`

   `d ) 3/2 : x = 7/4`

   `⇒ 3/2 = 7/4 x`

   `⇒ 4 . 3/2 = 7x`

   `⇒ 6 = 7x`

   `⇒ x = 6/7`

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2. `a)2/3 . x = 2/7`

   ` x = 2/7 : 2/3`

   ` x = 3/7`

   ` b) x . 3/5 = 2/5 `

    ` x = 2/5 : 3/5`

   ` x = 2/3`

   `c) x : 8/13 = 13/7`

   ` x = 13/7 . 8/13`

   ` x = 8/7`

   `d) 3/2 : x = 7/4`

   ` x = 3/2 : 7/4`

   ` x = 6/7`

    

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