Bài 1) Tìm x a) x + 7/12 = 17/18 – 1/9 b) 29/30 – (13/25 + x) = 7/69 c) x/2 – 2/5 = 1/10 d) 15/x –

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1. $#Hy$

   Bài 1:

   a) x + 7/12 = 17/18 – 1/9

    x + 7/12 = 17/18 – 2/18

    x + 7/12 = 15/18

    x = 15/18 – 7/12

    x = 5/6 – 7/12

    x = 10/12- 7/12

    x = 3/12

    x = 1/4

   Vậy x = 1/4

   b) 29/30 – (13/25 + x) = 7/69

   13/25 + x = 29/30 – 7/69

   13/25 + x = 29/30 – 7/69

   13/25 + x = 2001/2070 – 210/2070

   13/25 + x = 2001/2070 – 210/2070

   13/25 + x = 1791/2070

   13/25 + x = 199/230

   x = 199/230 – 13/25

   x = 4975/5750 – 2990/5750

   x = 1985/5750 

   x = 397/1150

   Vậy x = 397/1150

   c) x/2 – 2/5 = 1/10

   x/2 = 1/10 + 2/5

   x/2 = 1/10 + 4/10

   x/2 = 5/10

   x/2 = 1/2

   ⇒ x = 1

   Vậy x = 1

   d) 15/x – 1/3 = 28/51

   15/x = 28/51 + 1/3

   15/x = 28/51 + 17/51

   15/x = 45/51

   15/x = 15/17

   ⇒ x = 17

   Vậy x = 17

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