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

Toán Lớp 7: tìm x 1) |12-x|=3 2)|3x+4|=5 3)1/2+|x-2|=1 4)|1/2.x+1|-3/2=9 5)2.|3.x-2|=8

Tháng Mười Hai 29, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: tìm x
1) |12-x|=3
2)|3x+4|=5
3)1/2+|x-2|=1
4)|1/2.x+1|-3/2=9
5)2.|3.x-2|=8

Comments ( 2 )

  1. behocgioitoan
    behocgioitoan
    29 Tháng Mười Hai, 2022 at 1:45 chiều
    Reply
    Giải đáp + Lời giải và giải thích chi tiết:
    1)
    |12-x|=3
    to [(12-x=3),(12-x=-3):} to [(x=9),(x=15):}
    Vậy x in {9;15}
    2)
    |3x+4|=5
    to [(3x+4=5),(3x+4=-5):} to [(3x=1),(3x=-9):}
    to  \(\left[ \begin{array}{l}x=\dfrac{1}{3}\\x=-3\end{array} \right.\) 
    Vậy x in {-3;1/3}
    3)
    1/2+|x-2|=1
    to |x-2|=1-1/2
    to |x-2|=1/2
    to \(\left[ \begin{array}{l}x-2=\dfrac{1}{2}\\x-2=-\dfrac{1}{2}\end{array} \right.\) to \(\left[ \begin{array}{l}x=\dfrac{5}{2}\\x=\dfrac{3}{2}\end{array} \right.\) 
    Vậy x in {3/2;5/2}
    4)
    |1/2x+1|-3/2=9
    to |1/2x+1|=9+3/2
    to |1/2x+1|=21/2
    to \(\left[ \begin{array}{l}\dfrac{1}{2}x+1=\dfrac{21}{2}\\\dfrac{1}{2}x+1=-\dfrac{21}{2}\end{array} \right.\) to \(\left[ \begin{array}{l}x=19\\x=-23\end{array} \right.\) 
    Vậy x in {-23;19}
    5)
    2|3x-2|=8
    to |3x-2|=4
    to [(3x-2=4),(3x-2=-4):} to [(3x=6),(3x=-2):}
    to \(\left[ \begin{array}{l}x=2\\x=-\dfrac{2}{3}\end{array} \right.\) 
    Vậy x in {-2/3;2}

  2. annhocbichchaubich
    annhocbichchaubich
    29 Tháng Mười Hai, 2022 at 1:44 chiều
    Reply
    Chúc bạn học tốt

    toan-lop-7-tim-1-12-3-2-3-4-5-3-1-2-2-1-4-1-2-1-3-2-9-5-2-3-2-8

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

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