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

Toán Lớp 8: 13. Tìm x, biết: $2x-x^{2}=2$ 15.: Chứng minh rằng: $2^12}+1$ chia hết cho 17.

Toán Lớp 8: 13. Tìm x, biết: $2x-x^{2}=2$
15.: Chứng minh rằng: $2^12}+1$ chia hết cho 17.

Comments ( 2 )

  1. $@Mốc$
    Gửi pé nè ^^
    $#chucbanhoctotnhe;333$

    toan-lop-8-13-tim-biet-2-2-2-15-chung-minh-rang-2-12-1-chia-het-cho-17

  2. #Sad
    13)
    2x-x^2 = 2
    ⇔ 2x-x^2-2 = 0
    ⇔ -x^2+2x-2 = 0
    ⇔ -(x^2-2x+2) = 0
    ⇔ -(x^2-2x+1+1) = 0
    ⇔ -(x-1)^2-1 = 0
    ⇔ -(x-1)^2 = 1
    \text{→Vì} -(x-1)^2 <= 0 AA x
    \text{Mà} -(x-1)^2 = 1 \text{(vô lý)}
    \text{Vậy} x in \emptyset
    15)
    2^(12)+1
    = (2^4)^3+1
    = (16)^3+1
    = (16+1)(16^2+16+1^2)
    = 17. (16^2+16+1)
    \text{Vì} 17 \vdots 17
    ⇒ 17. (16^2+16+1) \vdots 17
    \text{Vậy} 2^(12)+1 \vdots 17
     

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

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