Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

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

Toán Lớp 7: Bài 5:Chứng minh rằng: A= $2^{20}$ – $2^{17}$ chia hết cho 7

Toán Lớp 7: Bài 5:Chứng minh rằng:
A= $2^{20}$ – $2^{17}$ chia hết cho 7

Comments ( 2 )

  1.  Ta có :
    2^20 – 2^17
    =  2^17 . 2^3 – 2^17
    =  2^17  . (2^3-1)
    =  2^17 . (8-1)
    = 2^17 . 7
    Vì 2^17 . 7 \in NN và 7 \vdots 7  nên : 2^17 . 7 \vdots 7
    => 2^20 – 2^17 \vdots 7

  2. A=2^20-2^17
    A=2^17*(2^3-1)
    A=2^17*(8-1)
    A=2^17*7\vdots7
    Vậy A\vdots7

Leave a reply

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

About Xuân