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 5: ( 1/3×5 + 1/ 5×7 + 1/7×9 +… + 1/9×11 ) x X = 8/11

Toán Lớp 5: ( 1/3×5 + 1/ 5×7 + 1/7×9 +… + 1/9×11 ) x X = 8/11

Comments ( 2 )

  1. (1/(3×5) + 1/(5×7) + 1/(7×9) + … + 1/(9×11) ) x X = 8/11
    (2/(3×5) + 2/(5×7) + … + 2/(9×11) ) x X = 16/11
    ( 1/3 – 1/5 + 1/5 -1/7 + 1/7 – 1/9 + 1/9 – 1/11 ) x X = 16/11
    (1/3 – 1/11) x X = 16/11
    8/33 x X = 16/11
    X = 16/11 : 8/33
    X = 16/11 x 33/8
    X = 2 x 3
    X = 6

  2. ( 1/{3 xx 5} + 1/{5xx7} + 1/{7xx9} + 1/{9xx11} ) xx x = 8/11
    ( 1/3 – 1/5 + 1/5 – 1/7 + 1/7 – 1/9 + 1/9 – 1/11 ) xx x = 8/11
    ( 1/3 – 1/11 ) xx x = 8/11
    10/33 xx x = 8/11
                   x = 8/11 : 10/33
                   x = 132/55
    Vậy x = 132/55
    #dtkc

Leave a reply

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