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

Toán Lớp 6: 100 mũ 2 -(x-12) mũ 2= (-8) mũ 2

Toán Lớp 6: 100 mũ 2 -(x-12) mũ 2= (-8) mũ 2

Comments ( 2 )

  1. Giải đáp:
    $100^{2} -(x-12)^{2}=(-8)^{2}$
    $(x-12)^2= 100^2-(-8)^2$
    $(x-12)^2= [100-(-8)]^2$
    $(x-12)^2= 108^2$
    $ x-12=108$
    $ x=108+12$
    $ x=120$
    $\text{Vậy x=120}$
     

  2. 100^2 – (x-12)^2 = (-8)^2
    => 1000 – (x-12)^2 = 64
    => (x-12)^2 = 100 – 64
    => (x-12)^2=36
    => (x-12)^2=6^2
    => \(\left[ \begin{array}{l}x-12=6\\x-12=-6\end{array} \right.\)
    => \(\left[ \begin{array}{l}x=18\\x=6\end{array} \right.\) 
    Vậy x∈{18;6}

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