a, 149-4.(x+25)=49 b, [ 2.(x+5)-31].4=52

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1. Đáp án:

   `149-4.(x+25)=49`

         ` 4.(x+25)=149-49`

          `4.(x+25)=100`

            `  x+25=100:4`

              `x+25=25`

            ` x=25-25`

             `x=0`

   `[ 2.(x+5)-31].4=52`

   `[2.(x+5)-31]=52:4`

   `[2.(x+5)-31]=13`

   `2.(x+5)=13+31`

   `2.(x+5)=44`

   `(x+5)=44:2`

   `(x+5)=22`

   `x+5=22-5`

   `x=17`

    

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2. Đáp án:

   ` 149 – 4(x+25) = 49`

   ` => -4(x+25) = 100`

   ` => x +25 = -25`

   ` => x = -25-25`

   ` => x = -50`

   Vậy ` x = -50`

   *****

   ` [ 2(x+5) – 31] . 4 = 52`

   ` => [2 (x+5) – 31] =  13`

   ` => 2(x+5) = 13 +31`

   ` => 2(x+5) = 44`

   ` => x +5 = 22`

   ` => x= 17`

    

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