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

Toán Lớp 6: B1 : Tìm x thuộc Z a. 25 – ( 30+ x ) = x – ( 27 – 8 ) b. ( x – 12 ) – 15 = ( 20 – 7 ) – ( 18 + x ) c. x + ( 17 – 8 ) = 5 + ( 10 – 3x

Toán Lớp 6: B1 : Tìm x thuộc Z
a. 25 – ( 30+ x ) = x – ( 27 – 8 )
b. ( x – 12 ) – 15 = ( 20 – 7 ) – ( 18 + x )
c. x + ( 17 – 8 ) = 5 + ( 10 – 3x )
d. 3( x – 3 ) – ( x + 1) = 12
e. 4( x – 1 ) – 2( x + 3 ) = 26
Chi tiết giúp mik vs ạ

Comments ( 2 )

  1. 25-(30+x)=x-(27-8)
    <=> 25 – 30 – x = x – 27 + 8
    <=> -5 – x = x – 19
    <=> -x – x = 5 – 19
    <=> -2x = -14
    <=> x = 7
    ————————————-
    (x-12)-15=( 20 – 7 ) – ( 18 + x )
    <=> x – 12 – 15 = 20 – 7 – 18 – x
    <=> x – 27 = -5 – x
    <=> x+ x = 27 – 5
    <=> 2x = 22
    <=>x = 11
    —————————————–
    x + ( 17 – 8 ) = 5 + ( 10 – 3x )
    <=> x + 17 – 8 = 5 + 10 – 3x
    <=> x + 9 = 15 – 3x
    <=>  x + 3x = -9 + 15
    <=> 4x = 6
    <=> x = 3/2
    ———————————————-
    3( x – 3 ) – ( x + 1) = 12
    <=> 3x – 9 – x – 1 = 12
    <=> 2x -10=12
    <=> 2x=22
    <=> x=11
    ————————————-
    4( x – 1 ) – 2( x + 3 ) = 26
    <=> 4x-4-2x-6=26
    <=> 2x-10=26
    <=> 2x=36
    <=> x=18

  2. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    B1 : Tìm x thuộc Z
    a. 25 – ( 30+ x ) = x – ( 27 – 8 )
    ⇔25-30-x=x-19
    ⇔-5-x=x-19
    ⇔-5-x-x+19=0
    ⇔14-2x=0
    ⇔2x=14
    ⇔x=14:2
    ⇔x=2
    Vậy x=2
    b. ( x – 12 ) – 15 = ( 20 – 7 ) – ( 18 + x )
    ⇔x-12-15=13-18-x
    ⇔x-27=-5-x
    ⇔x-27+5+x=0
    ⇔2x-22=0
    ⇔2x=22
    ⇔x=22:2
    ⇔x=11
    Vậy x=11
    c. x + ( 17 – 8 ) = 5 + ( 10 – 3x )
    ⇔x+9=5+10-3x
    ⇔x+9=15-3x
    ⇔x+9-15+3x=0
    ⇔4x-6=0
    ⇔2.(2x-3)=0
    ⇔2x-3=0
    ⇔2x=3
    ⇔x=3/2
    Vậy x=3/2
    d. 3( x – 3 ) – ( x + 1) = 12
    ⇔3x-9-x-1=12
    ⇔2x-10=12
    ⇔2x=22
    ⇔x=22:2
    ⇔x=11
    Vậy x=11
    e. 4( x – 1 ) – 2( x + 3 ) = 26
    ⇔4x-4-2x-6=26
    ⇔2x-10=26
    ⇔2x=36
    ⇔x=36:2
    ⇔x=18
    Vậy x=18

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