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

Toán Lớp 8: Tìm x 1) [2x – 1]/[x^2 + 4x – 5] + [x-2]/[x^2 – 10x +9] = 3x – 12/x^4 – 4x – 45

Toán Lớp 8: Tìm x
1) [2x – 1]/[x^2 + 4x – 5] + [x-2]/[x^2 – 10x +9] = 3x – 12/x^4 – 4x – 45

Comments ( 1 )

  1. ~ gửi bạn ~
    Giải đáp:
    x = -18 
    Lời giải và giải thích chi tiết:
    1)
    [2x – 1]/[x^2 + 4x – 5] + [x-2]/[x^2 – 10x +9] = [3x – 12]/[x^2 – 4x – 45]
    <=> [2x – 1]/[x^2 -x + 5x – 5] + [x-2]/[x^2 -x – 9x +9] – [3x – 12]/[x^2 + 5x – 9x – 45] = 0
    <=> [2x – 1]/[(x – 1).(x + 5)] + [x-2]/[(x – 1).(x – 9)] – [3x – 12]/[(x + 5).(x – 9)] = 0
    => (2x−1).(x−9)+(x−2).(x+5)−(3x−12).(x−1)=0
    ⇔2x^2−19x+9+x^2+3x−15−3x^2+15x−12=0
    <=> (2x^2 + x^2 – 3x^2) + (-19x+ 3x + 15x) + (9 – 15 -12) = 0
    <=> -x – 18 = 0
    <=> -x  = 18
    <=> x = -18
    Vậy x = -18

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

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