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

Toán Lớp 7: 1) Tìm x a) 13/19 – 3/8 < x - 1/5 < 11/15 + 2/3 b)1/3 +2/7 < 0.5 - 2/3x < 3/4 + 0,25

Toán Lớp 7: 1) Tìm x
a) 13/19 – 3/8 < x - 1/5 < 11/15 + 2/3 b)1/3 +2/7 < 0.5 - 2/3x < 3/4 + 0,25

Comments ( 2 )

  1. Lời giải và giải thích chi tiết:
     a)
    13/19 – 3/8 < x – 1/5 < 11/15 + 2/3
    => 47/152 < x – 1/5 < 7/5
    => 47/152 + 1/5 < x < 7/5 + 1/5
    => 387/760 < x < 8/5
    => 0,5 < x < 1,6
    => x in {0,6; 0,7; 0,8; …; 1,5; 1,6}
    $\\$
    b)
    1/3 +2/7 < 0.5 – 2/3x < 3/4 + 0,25
    =>13/21 < 0.5 – 2/3x < 1
    =>13/21 – 0.5 < -2/3x < 1 – 0,5
    =>5/42 < -2/3x < 1/2
    =>5/42 : -2/3< x < 1/2 : -2/3
    =>-5/28 < x < -3/4
    =>-0,18 < x < -0,75
    => x = -0,1

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