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

Toán Lớp 10: (x^2 + 2x – 4)(x^2 + 2x – 2) = 8

Tháng Tư 21, 2022 Toán học 1 Comment 0 views

Toán Lớp 10: (x^2 + 2x – 4)(x^2 + 2x – 2) = 8

Comments ( 1 )

  1. minhtuquynh
    minhtuquynh
    21 Tháng Tư, 2022 at 2:09 chiều
    Reply
    (x^2 + 2x – 4).(x^2 + 2x – 2) = 8
    Gọi x^2 + 2x là t
    -> ( t – 4).(t-2) = 8
    <=> t^2 – 6t + 8 = 8
    <=> t^2 – 6t = 0
    <=> t.(t-6) = 0
    => {{:(t=0),(t-6=0):}
    Ta thay vào:
    => {{:(x^2+2x=0),(x^2+2x – 6=0):}
    <=> {{:(x.(x+2)=0),(x=-1+sqrt7),(x=-1-sqrt7):}
    => {{:(x=0),(x=-2),(x=-1+sqrt7),(x=-1-sqrt7):}
    Vậy x in {0;-2;-1+sqrt7;-1-sqrt7}

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

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