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

Toán Lớp 8: (x – 1)^3 – x(x – 2)^2 = x( x+3) -12

Toán Lớp 8: (x – 1)^3 – x(x – 2)^2 = x( x+3) -12

Comments ( 2 )

  1. Giải đáp:
    x = 11/4
    Lời giải và giải thích chi tiết:
    (x – 1)^3 – x(x – 2)^2 = x(x + 3) – 12
    (x^3 – 3x^2 + 3x – 1) – x(x^2 – 4x + 4) = x(x + 3) – 12
    x^3 – 3x^2 + 3x – 1 – x^3 + 4x^2 – 4x = x(x + 3) – 12
    (x^3 – x^3) – (3x^2 – 4x^2) + (3x – 4x) – 1  = x^2 + 3x – 12
    – ( – x^2) – x – 1 – (x^2 + 3x – 12) = 0
    x^2 – x – 1 – (x^2 + 3x – 12) = 0
    x^2 – x – 1 – x^2 – 3x + 12 = 0
    (x^2 – x^2) – (x + 3x) – (1 – 12) = 0
    – 4x – ( – 11) = 0
    – 4x + 11 = 0
    – 4x = – 11
    x = {-11}/{-4} = 11/4
    Vậy x = 11/4
    #SunHee

  2. Giải đáp:
     x=11/4
    Lời giải và giải thích chi tiết:
    (x-1)^3-x(x-2)^2=x(x+3)-12
    x^3-3x^2+3x-1-x(x^2-4x+4)=x^2+3x-12
    x^3-3x^2+3x-1-x^3+4x^2-4x-x^2-3x+12=0
    -4x+11=0
    -4x=-11
    x=11/4

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