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

Toán Lớp 8: `PTĐTTNT` `(x^2+x)^2+4(x^2+x)-12`

Toán Lớp 8: PTĐTTNT
(x^2+x)^2+4(x^2+x)-12

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    Đặt x^2 + x = t ta có:
    t^2 + 4t – 12
    = t^2 – 2t + 6t – 12
    = (t^2 – 2t) + (6t – 12)
    = t(t – 2) + 6(t – 2)
    = (t – 2)(t + 6)
    Thay x = x^2 + x ta có:
    (x^2 + x – 2)(x^2 + x + 6)
    = (x^2 + 2x – x – 2)(x^2 + x – 6)
    = [(x^2 + 2x) – (x + 2)](x^2 + x – 6)
    = [x(x + 2) – (x + 2)](x^2 + x – 6)
    = (x + 2)(x – 1)(x^2 + x – 6)
    #SunHee

  2. (x^2+x)^2+4(x^2+x)-12
    Đặt x^2+x=t ta được:
    t^2+4t-12
    =t^2+6t-2t-12
    =(t^2+6t)-(2t+12)
    =t(t+6)-2(t+6)
    =(t-2)(t+6)
    =(x^2+x-2)(x^2+x+6)
    =(x^2+2x-x-2)(x^2+x+6)
    =[(x^2+2x)-(x+2)](x^2+x+6)
    =[x(x+2)-(x+2)](x^2+x+6)
    =(x-1)(x+2)(x^2+x+6)
    \text{#Familyisnumber1}

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