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

Toán Lớp 8: Phân tích các đa thức sau thành nhân tử. a, x4 + x3 – x2 – 1 b, x4 – 3×3 – x + 3 c,3x + 3y – x2 – 2xy – y2 d, 2x – 2y – x2 + 2xy – y2 e

Toán Lớp 8: Phân tích các đa thức sau thành nhân tử.
a, x4 + x3 – x2 – 1
b, x4 – 3×3 – x + 3
c,3x + 3y – x2 – 2xy – y2
d, 2x – 2y – x2 + 2xy – y2
e, x2y – y3 – 2y2 – y
f, x3z + 2x2yz + xy2z – 9xz
Giúp mik vs

Comments ( 1 )

  1. Hướng dẫn trả lời:
    a) x^4 + x^3 – x^2 – 1.
    = x^4 + 2x^3 + x^2 + x – x^3 – 2x^2 – x – 1.
    = (x^4 + 2x^3 + x^2 + x) – (x^3 + 2x^2 + x + 1).
    = x.(x^3 + 2x^2 + x + 1) – (x^3 + 2x^2 + x + 1).
    = (x – 1).(x^3 + 2x^2 + x + 1).
    b) x^4 – 3x^3 – x + 3.
    = (x^4 – x) – (3x^3 – 3).
    = x.(x^3 – 1) – 3.(x^3 – 1).
    = (x – 3).(x^3 – 1).
    = (x – 3).(x – 1).(x^2 + x + 1).
    c) 3x + 3y – x^2 – 2xy – y^2.
    = (3x + 3y) – (x^2 + 2xy + y^2).
    = 3.(x + y) – (x + y)^2.
    = (x + y).[3 – (x + y)].
    = (x + y).(3 – x – y).
    d) 2x – 2y – x^2 + 2xy – y^2.
    = (2x – 2y) – (x^2 – 2xy + y^2).
    = 2.(x – y) – (x – y)^2.
    = (x – y).[2 – (x – y)].
    = (x – y).(2 – x + y).
    = – (x – y).(x – y – 2).
    e) x^2y – y^3 – 2y^2 – y.
    = y.(x^2 – y^2 – 2y – 1).
    = y.[x^2 – (y^2 + 2y + 1)].
    = y.[x^2 – (y + 1)^2].
    = y.[x + (y + 1)].[x – (y + 1)].
    = y.(x + y + 1).(x – y – 1).
    f) x^3z + 2x^2yz + xy^2z – 9xz.
    = xz.(x^2 + 2xy + y^2 – 9).
    = xz.[(x^2 + 2xy + y^2) – 9].
    = xz.[(x + y)^2 – 3^2].
    = xz.[(x + y) + 3].[(x + y) – 3].
    = xz.(x + y + 3).(x + y – 3).

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

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