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: c/m 5^2014-5^2013+5^2012chia hết cho 105

Toán Lớp 7: c/m 5^2014-5^2013+5^2012chia hết cho 105

Comments ( 2 )

  1. 5^2014 – 5^2013 + 5^2012
    = 5^2011 . (5^3 – 5^2 + 5)
    = 5^2011 . (125 – 25 + 5)
    = 5^2011 . 105
    mà 105 vdots 105
    => 5^2014 – 5^2013 + 5^2012 vdots 105
     

  2. Lời giải chi tiết:
    5^2014-5^2013+5^2012
    =5^2012.(5^2-5+1)
    =5^(2012).21
    =5^(2011).5.21
    =5^(2011).105\vdots105
    Vậy 5^2014-5^2013+5^2012\vdots105

Leave a reply

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