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

Toán Lớp 6: d) 3 ngũ 2 x ( x + 4 ) – 5 ngũ 2 = 5 . 2 ngũ 2 e) x là ƯCLN CỦA ( 48 ; 72 ; 84 )

Toán Lớp 6: d) 3 ngũ 2 x ( x + 4 ) – 5 ngũ 2 = 5 . 2 ngũ 2
e) x là ƯCLN CỦA ( 48 ; 72 ; 84 )

Comments ( 2 )

  1. d) 3^2 . (x + 4) – 5^2 = 5 . 2^2
    9 . (x + 4) – 25 = 5 . 4
    9 . (x + 4) – 25 = 20
    9 . (x + 4) = 20 + 25
    9 . (x + 4) = 45
    x + 4 = 45 : 9
    x + 4 = 5
    x = 5 – 4
    x = 1
    Vậy x = 1
    _______________________________________
    e) Ta có :
    x in ƯCLN(48; 72; 84)
    48 = 2^4 . 3
    72 = 2^3 . 3^2
    84 = 2^2 . 3 . 7
    ƯCLN(48; 72; 84) = 2^2 . 3 = 4 . 3 = 12
    Vậy x = 12

  2. d, 3^2 . (x + 4) – 5^2 = 5 . 2^2
    => 9 . (x + 4) – 25 = 5 . 4
    => 9x + 36 – 25 = 20
    => 9x + 11 = 20
    => 9x = 20 – 11 = 9
    => x = 9 : 9
    => x = 1
    Vậy x = 1
    e,
    48 = 2^4 . 3
    72 = 2^3 . 3^2
    84 = 2^2 . 3 . 7
    => ƯCLN (48 ; 72 ; 84) = 2^2 . 3 = 4 . 3 = 12
    Vậy x = 12

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

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