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

Toán Lớp 6: Tìm số nguyên a, bt: a) 27 – (5 – |a|) = 31 b) -13 – (6 – |a + 1| = 24) Ko chép mạng nha !!!!!

Toán Lớp 6: Tìm số nguyên a, bt:
a) 27 – (5 – |a|) = 31
b) -13 – (6 – |a + 1| = 24)
Ko chép mạng nha !!!!!

Comments ( 2 )

  1. a)27 – (5 – |a|) = 31
    =>5 – |a|=27-31
    =>5 – |a|=-4
    =>|a|=5 -(-4)
    =>|a|=9
    =>a=±9
    b) -13 – (6 – |a + 1|) = 24
    =>6 – |a + 1|=-13-24
    =>6 – |a + 1|=-37
    =>|a + 1|=6 -(-37)
    =>|a + 1|=43
    =>\(\left[ \begin{array}{l}a+1=43\\a+1=-43\end{array} \right.\)
    =>\(\left[ \begin{array}{l}a=43-1\\a=-43-1\end{array} \right.\)
    =>\(\left[ \begin{array}{l}a=42\\a=-44\end{array} \right.\) 
    vậy a∈{42;-44}
     

  2. Giải đáp:
    a, 27 – (5 – |a|) = 31
    27 – 5 + |a| = 31
    -> 22 + |a| = 31
    -> |a| = 31 – 22
    -> |a| = 9
    -> a = +-9
    Vậy a = +-9
    b, -13 – (6 – |a + 1|) = 24
    -13 – 6 + |a+1| = 24
    -19 + |a+1| = 24
    -> |a+1| = 43
    -> $\left[\begin{matrix} a+1 = 43\\ a+1 = -43\end{matrix}\right.$
    -> $\left[\begin{matrix} a = 42\\ a = -44\end{matrix}\right.$
    Vậy a in {42 , -44}
     

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