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: M=2^2020-(2^2019+2^2018+…+2^1+2^0)

Toán Lớp 7: M=2^2020-(2^2019+2^2018+…+2^1+2^0)

Comments ( 2 )

  1. Lời giải và giải thích chi tiết:
    M = 2^2020 – ( 2^2019 + 2^2018 +……..+ 2^1 + 2^0 )
    -Đặt P =  2^2019 + 2^2018 +……..+ 2^1 + 2^0
    => 2P = 2^2020 + 2^2019 +……+ 2^2 + 2^1
    => 2P – P = 2^2020 – 2^0
    => P = 2^2020 – 1
    => M = 2^2020 – ( 2^2020 – 1 )
    => M = 2^2020 – 2^2020 + 1
    => M = 1

  2. Lời giải và giải thích chi tiết:
    Ta có: 
    M=2^2020-(2^2019+2^2018+…+2^1+2^0)
    Đặt S=2^2019+2^2018+…+2^1+2^0
    ⇒2S=2^2020+2^2019+2^2018+…+2^1
    ⇒2S-S=(2^2020+2^2019+2^2018+…+2^1)-(2^2019+2^2018+…+2^1+2^0)
    ⇒S=2^2020-2^0
    ⇒S=2^2020-1
    ⇒M=2^2020-(2^2020-1)
    ⇒M=2^2020-2^2020+1
    ⇒M=1

Leave a reply

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