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

Toán Lớp 6: Bài1: Tìm x biết a) 36 . x = -108 b) x . (- 5 ) = 125 c) x² = 9 d) x³ = – 8

Toán Lớp 6: Bài1: Tìm x biết
a) 36 . x = -108
b) x . (- 5 ) = 125
c) x² = 9
d) x³ = – 8

Comments ( 2 )

  1. Giải đáp:
     $a) 36.x=-108$
    $⇔ x= -108:36$
    $⇔ x= -3$
    $vậy$ $x=-3$
    $b) x.(-5)=125$
    $⇔ x=125:(-5)$
    $⇔ x= -25$
    $Vậy$ $x=-25$
    $c) x²=9$
    $⇔ x²=3²$
    $⇔$ \(\left[ \begin{array}{l}x-3=0\\x+3=0\end{array} \right.\) $⇔$  \(\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.\) 
    $vậy$ $\text{x ∈ {±3}}$
    $d) x³=-8$
    $⇔ x³=(-2)³$
    $⇔ x=-2$
    $vậy$ $x=-2$
     

  2. a) 36 . X = -108
               X= -108:36
               X=-3
    b) X. (- 5 ) = 125
        X=125:-5
        X= -25
        c) x² = 9
           ????²−9=0
           ????=3
    d) x³ = – 8
        X³=(-2³)
        X=-2
       
     

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