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

Toán Lớp 6: a) 27^5 . 3^x = 9^8 b) 5^8-x = 5^x . 25 c) 2^x+2 – 2x = 96

Toán Lớp 6: a) 27^5 . 3^x = 9^8
b) 5^8-x = 5^x . 25
c) 2^x+2 – 2x = 96

Comments ( 2 )

  1. Giải đáp:
    a,275.3x=98
    Vậy x=1
    58-x=5x.52
    2x.22-2x=96
    Vậy 
     

  2. a, 27^5. 3^x = 9^8
    => (3^3)^5. 3^x = (3^2)^8
    => 3^15. 3^x = 3^16
    => 3^x = 3^16 : 3^15
    => 3^x = 3^1
    => x = 1
    Vậy x = 1
    b,
    5^(8 – x) = 5^x. 25
    =>5^(8 – x) = 5^x. 5^2
    => 5^(8 – x) = 5^(x+2)
    => 8 – x = x + 2
    => x + x = 8 – 2
    => 2x = 6
    => x = 3
    c,
    2^(x+2) – 2^x = 96
    => 2^x. 2^2 – 2^x = 96
    => 2^x. (2^2 – 1) = 96
    => 2^x. 3 = 96
    => 2^x = 96 : 3
    => 2^x = 32
    => 2^x = 2^5
    => x = 5
    Vậy x = 5
     

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

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