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

Toán Lớp 6: Bài 2 Tìm x, biết a) 4.(3x-4)-2=18 b) B={x∈ N/30< x ≤40} c) (105-x) : 2^5=3^0 +1 d) 2x-138=2 ².3 ² e) (6x-39).28=5628 f) (9x+2).3

Toán Lớp 6: Bài 2 Tìm x, biết
a) 4.(3x-4)-2=18
b) B={x∈ N/30< x ≤40} c) (105-x) : 2^5=3^0 +1 d) 2x-138=2 ².3 ² e) (6x-39).28=5628 f) (9x+2).3=60 g) (26-3x):5+71=75 h) 5^x+1=125

Comments ( 2 )

  1. Giải đáp:
    Câu 2:
    a, 4(3x-4)-2=18
    <=> 4(3x-4)=20
    <=> 3x-4=5
    <=> 3x=9
    <=> x=3
    Vậy x=3
    b, B={x\inNN|30<x<=40}
    <=> B={31;32;33;…;40}
    Vậy B={31;32;33;…;40}
    c, (105-x):2^5=3^0+1
    <=> (105-x):2^5=2
    <=> 105-x=64
    <=> x=41
    Vậy x=41
    d, 2x-138=2^2 .3^2
    <=> 2x-138=36
    <=> 2x=174
    <=> x=87
    Vậy x=87
    e, (6x-39).28=5628
    <=> 6x-39=201
    <=> 6x=240
    <=> x=40
    Vậy x=40
    f, (9x+2).3=60
    <=> 9x+2=20
    <=> 9x=18
    <=> x=2
    Vậy x=2
    g, (26-3x):5+71=75
    <=> (26-3x):5=4
    <=> 26-3x=20
    <=> 3x=6
    <=> x=2
    Vậy x=2
    h, 5^(x+1)=125
    <=> 5^(x+1)=5^3
    <=> x+1=3
    <=> x=2
    Vậy x=2

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