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

Toán Lớp 6: Bài11 : Tìm x, biết. a. 2(x – 5) – 3(x + 7) = 14 b. 5(x – 6) – 2(x + 3) = 12 c. 3(x – 4) – (8 – x) = 12 d. -7(3x – 5)

Tháng Ba 18, 2023 Toán học 0 Comments 0 views

Toán Lớp 6: Bài11 : Tìm x, biết.
a. 2(x – 5) – 3(x + 7) = 14
b. 5(x – 6) – 2(x + 3) = 12
c. 3(x – 4) – (8 – x) = 12
d. -7(3x – 5) + 2(7x – 14) = 28
e. 5(3 – 2x) + 5(x – 4) = 6 – 4x
f. -5(2 – x) + 4(x – 3) = 10x – 15

Comments ( 2 )

  1. tuyethutanhthu
    tuyethutanhthu
    18 Tháng Ba, 2023 at 2:48 chiều
    Reply
    Giải đáp:
    a) x = – 45
    b) x = 16
    c) x = 8
    d) x = – 3
    e) x = – 11
    f) x = – 7
    Lời giải và giải thích chi tiết:
    Bài 11 :
    a) 2 . ( x – 5 ) – 3 . ( x + 7 ) = 14
    => 2x – 10 – 3x – 21 = 14
    => 2x – 3x = 14 + 21 + 10
    => – x = 45
    => x = – 45
    Vậy x = – 45
    b) 5 . ( x – 6 ) – 2 . ( x + 3 ) = 12
    => 5x – 30 – 2x – 6 = 12
    => ( 5x – 2x ) – ( 30 + 6 ) = 12
    => 3x = 12 + 36
    => 3x = 48
    => x = 48/3 = 16
    Vậy x = 16
    c) 3 . ( x – 4 ) – ( 8 – x ) = 12
    => 3x – 12 – 8 + x = 12
    => 3x + x = 12 + 12 + 8
    => 4x = 24 + 8
    => 4x = 32
    => x = 32/4 = 8
    Vậy x = 8
    d) – 7 . ( 3x – 5 ) + 2 . ( 7x – 14 ) = 28
    => – 21x + 35 + 14x – 28 = 28
    => – 21x + 14x = 28 + 28 – 35
    => – 7x = 21
    => x = 21/(-7) = – 3
    Vậy x = – 3
    e) 5 . ( 3 – 2x ) + 5 . ( x – 4 ) = 6 – 4x
    => 15 – 10x + 5x – 20 = 6 – 4x
    => – 10x + 5x + 4x = 6 – 15 + 20
    => – x = 11
    => x = – 11
    Vậy x = – 11
    f) – 5 . ( 2 – x ) + 4 . ( x – 3 ) = 10x – 15
    => – 10 + 5x + 4x – 12 = 10x – 15
    => – 10 – 12 + 15 = 10x – 5x – 4x
    => – 7 = x
    Vậy x = – 7

  2. catlantuong
    catlantuong
    18 Tháng Ba, 2023 at 2:48 chiều
    Reply
    Đáp án:
    a) 2. ( x-5) -3. (x+7)= 14
    <=> 2x-10 -3x-21=14
    <=> -x -31=14
    <=> x=-31-14
    <=> x=-45                      
    b) 5(x-6)-2(x+3)=12
    <=>5x-30-2x-6=12
    <=>3x-36=12
    <=>3x=48
    <=>x=16
    c) 5(x-6)-2(x+3)=12
    <=>5x-30-2x-6=12
    <=>3x-36=12
    <=>3x=48
    <=>x=16
    d)
    ⇔-7(3x – 5) + 2(7x – 14) = 28
    ⇔-21x+35+14x-28=28
    ⇔-21x+14x+35-56=0
    ⇔-21x+14x-21=0
    ⇔-7x-21=0
    ⇔-7(x+3)=0
    ⇔x+3=0
    ⇔x=-3
    e. 5(3 – 2x) + 5(x – 4) = 6 – 4x
    ⇒15-10x+5x-20=6-4x
    ⇒ 15-10x+5x-20-6+4x=0
    ⇒ -11-x=0
    ⇒ x=-11
    F.5(2 – x) + 4(x – 3) = 10x – 15
    <=> -10 +5x +4x -12 = 10x-15
    <=> 5x+4x-10x= -15 +10 +12
    <=> -x=7
    <=> x=-7
    #nocopy 
    Cho mik ctlhn với
     

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

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