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

Toán Lớp 8: Tìm x,biết: a/4.(18-5x)-12.(3x-7)=15.(2x-16)-6.(x+14) b/2.(5x-8)-3.(4x-5)=4.(3x-4)+11 c/(x+2).(x+3)-(x-2).(x+5)=6 d/3.(2x-1).(3x-1)-(2x

Tháng Mười Hai 26, 2022 Toán học 1 Comment 0 views

Toán Lớp 8: Tìm x,biết:
a/4.(18-5x)-12.(3x-7)=15.(2x-16)-6.(x+14)
b/2.(5x-8)-3.(4x-5)=4.(3x-4)+11
c/(x+2).(x+3)-(x-2).(x+5)=6
d/3.(2x-1).(3x-1)-(2x-3).(9x-1)=0

Comments ( 1 )

  1. quynhmaithu
    quynhmaithu
    26 Tháng Mười Hai, 2022 at 10:23 chiều
    Reply
    a) 4.(18-5x)-12.(3x-7)=15.(2x-16)-6.(x+14)
    <=> 72 – 20x – 36x + 84 = 30x – 240 – 6x – 84
    <=> -80x = -480
    <=> x = 6
    Vậy x = 6
    b) 2.(5x-8)-3.(4x-5)=4.(3x-4)+11
    <=> 10x – 16 – 12x + 15 = 12x – 16 + 11
    <=> -14x = -4
    <=> x = 2/7
    Vậy x = 2/7
    c) (x+2).(x+3)-(x-2).(x+5)=6
    <=> x^2 + 5x + 6 – x^2 – 3x + 10 = 6
    <=> 2x = -10
    <=> x = -5
    Vậy x = -5
    d) 3.(2x-1).(3x-1)-(2x-3).(9x-1)=0
    <=> 18x^2 – 15x + 3 – 18x^2 + 29x – 3 = 0
    <=> 14x = 0
    <=> x = 0
    Vậy x = 0

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

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