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

Toán Lớp 8: Phân tích thành nhân tử: a(b² + c²) + b(c² + a²) + c(a² + b²) – 2abc – a³ – b³ – c³

Toán Lớp 8: Phân tích thành nhân tử:
a(b² + c²) + b(c² + a²) + c(a² + b²) – 2abc – a³ – b³ – c³

Comments ( 2 )

  1. Giải đáp:
     a(b^2 + c^2) + b(c^2 + a^2) + c(a^2 + b^2) – 2abc – a^3 – b^3 – c^3
    = [a(b^2 + c^2) – 2abc – a^3] + bc^2 + a^2 b + a^2 c + b^2 c – b^3 – c^3
    = a(b^2 + c^2 – 2bc – a^2) + (bc^2 – b^3) + (a^2 b + a^2 c) + (b^2 c – c^3)
    = a[(b – c)^2 – a^2] + b(c^2 – b^2) + a^2 (b +c) + c(b^2 – c^2)
    = a[(b – c)^2 – a^2] + b(c – b)(c +b) + a^2 (b + c) + c(b – c)(b + c)
    = a[(b – c)^2 – a^2] + (b + c)[b(c – b) + a^2 + c(b – c)]
    = a[(b – c)^2 – a^2] + (b + c)(bc – b^2 + a^2 + bc – c^2)
    = – a[a^2 – (b – c)^2] + (b + c)[a^2 – (b^2 – 2bc + c^2)]
    = – a[a^2 – (b – c)^2] + (b + c)[a^2 – (b – c)^2]
    = – a(a – b + c)(a + b – c) + (b + c)((a – b + c)(a + b – c)
    = (a – b + c)(a + b – c)(b + c – a)

  2. Lời giải và giải thích chi tiết:
       a(b² + c²) + b(c² + a²) + c(a² + b²) – 2abc – a³ – b³ – c³
    = a(b² – 2bc + c²- a²) + b(a² + 2ac + c² – b²) + c(a² – 2ab + b² – c²)
    = a[(b – c)²- a²] + b[(a² + c)² – b²] + c[(a – b)² – c²]
    = a(c – b + a)(a + b – c) + b(a + c – b)(a + c + b) + c(a – b + c)(a – b – c)
    = (a + c – b).[a(c – b + a) + b(a + c + b) + c(a – b – c)]
    = (a + c – b)(b + a – c)(c + b – a)
    Chúc bạn học tốt nhé

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

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