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

Toán Lớp 6: tìm số nguyên x, biết: a)4.(x+2)^3-7=101. b)x-8=(-15)+(+29). c)10-(31-x)=40.

Toán Lớp 6: tìm số nguyên x, biết:
a)4.(x+2)^3-7=101.
b)x-8=(-15)+(+29).
c)10-(31-x)=40.

Comments ( 2 )

  1. Giải đáp:
     $a) 4.(x+2)³-7=101$
    $⇔ 4.(x+2)³= 108$
    $⇔ (x+2)³= 108:4$
    $⇔ (x+2)³= 27$
    $⇔ (x+2)³=3³$
    $⇔ x+2=3$
    $⇔ x=1$
    $vậy$ $x=1$
    $b) x-8= (-15)+(+29)$
    $⇔ x-8= 29-15$
    $⇔ x-8=14$
    $⇔ x=14+8$
    $⇔ 22$
    $vậy$ $x=22$
    $c) 10-(31-x)=40$
    $⇔ 31-x= 10-40$
    $⇔ 31-x= -30$
    $⇔ x= 31-(-30)$
    $⇔ x= 61$
    $vậy$ $x=61$ 
     

  2. $ a)4.(x+2)^3-7=101 $
    $ 4.(x+2)^3=101+7=108 $ 
    $ (x+2)^3=108:4=27=3^3⇒x+2=3⇒x=3-2=1 $
    $ b)x-8=(-15)+(+29)=(-15)+29=14 $ 
    $ x=14+8=22 $ 
    $ c) 10-(31-x)=40 $ 
    $ 10-31+x=40 $ 
    $ -21+x=40 ⇒x=40-(-21)=40+21=61 $

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