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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Tìm x : a) 3 . x +96 = 12 . 17 – 9 b) ( x +1) + (x + 2) + (x + 3) + (x + 4) + (x +5) = 560 c) 7 . ( x – 1) = 3 . x + 21 d) 30 – 2 . x

Toán Lớp 6: Tìm x :
a) 3 . x +96 = 12 . 17 – 9
b) ( x +1) + (x + 2) + (x + 3) + (x + 4) + (x +5) = 560
c) 7 . ( x – 1) = 3 . x + 21
d) 30 – 2 . x = 40 – 4 . x
Ai làm trước mình cho 5 sao

Comments ( 2 )

  1. y10000
    a )
    3x + 96 = 12.17 – 9 
    <=> 3x + 96 = 195
    <=> 3x = 99
    <=> x = 33
    b )
    ( x +1) + (x + 2) + (x + 3) + (x + 4) + (x +5) = 560
    <=> x +1 + x + 2 + x + 3 + x + 4 + x + 5= 560
    <=> 5x + 15 = 560
    <=> 5x = 545
    <=> x = 109
    c )
    7 . ( x – 1) = 3 . x + 21
    <=> 7x – 7 = 3x + 21
    <=> 7x – 3x = 21 + 7
    <=> 4x = 28
    <=> x = 7
    d )
    30 – 2 . x = 40 – 4 . x
    <=> -2x + 4x = 40 – 30
    <=> 2x = 10
    <=> x =5

  2. a) 3 . x + 96 = 12 . 17 – 9
     ⇒ 3x + 96   = 204 – 9
     ⇒ 3x + 96    = 195
     ⇒       3x       = 99
     ⇒         x       = 33
           Vậy x = 33
    b) ( x +1) + (x + 2) + (x + 3) + (x + 4) + (x +5) = 560
      ⇒ ( x + x + x + … + x ) + ( 1 + 2 + 3 + 4 + 5 ) = 560
      ⇒                             5x + 15                             = 560
      ⇒                                   5x                                = 545
      ⇒                                     x                                = 109
                             Vậy x = 109
    c)  7 . ( x – 1) = 3 . x + 21
     ⇒    7x – 7    = 3x + 21
     ⇒    7x – 3x   =  21 + 7
     ⇒        4x      = 28
     ⇒          x      = 7
                 Vậy x = 7
    d) 30 – 2 . x = 40 – 4 . x
     ⇒ -2x + 4x  = 40 – 30
     ⇒        2x     = 10
     ⇒         x      = 5
              vậy x = 5          

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222-9+11+12:2*14+14 = ? ( )

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