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

Toán Lớp 8: Phân tích các đa thức sau thành nhân tử a) 4x^2- 6x b) 3x (x-1) +5(x-1 ) c) 4x^2 -12x+9 d) ( 3x-1)^2 -16 e) x^3 +6x^2 +12x+8 f) 8

Toán Lớp 8: Phân tích các đa thức sau thành nhân tử
a) 4x^2- 6x
b) 3x (x-1) +5(x-1 )
c) 4x^2 -12x+9
d) ( 3x-1)^2 -16
e) x^3 +6x^2 +12x+8
f) 8x^3 -64
h) 5x^3 -5x^2y -10x^2 +10xy

Comments ( 2 )

  1. a) 4x^2- 6x $\\$<=>2x(2x-3)
    b) 3x (x-1) +5(x-1 ) $\\$<=>(3x+5)(x-1)
    c) 4x^2 -12x+9 $\\$<=>(2x)^2-2x.2.3+(3)^2$\\$<=>(2x-3)^2
    d) ( 3x-1)^2 -16 $\\$<=>(3x-1)^2-4^2$\\$<=>(3x-1+4)(3x+1+4)$\\$<=>(3x-3)(3x+5)
    e) x^3 +6x^2 +12x+8 $\\$<=>(x+2)^3
    f) 8x^3 -64$\\$<=>(2x)^3-4^3$\\$<=>(2x-4)(4x^2+8x+16)
    h) 5x^3 -5x^2y -10x^2 +10xy$\\$<=>5x^2(x-y)-10x^2(x-y)$\\$<=>5x(x-y)(x-2)

  2. Lời giải và giải thích chi tiết:
    a)
    4x^2 – 6x
    = 2x(2x – 3)
    b)
    3x(x – 1) + 5(x – 1)
    = (x – 1)(3x + 5)
    c)
    4x^2 – 12x + 9
    = (2x)^2 – 2 . 2x . 3 + 3^2
    = (2x – 3)^2
    d)
    (3x – 1)^2 – 16
    = (3x – 1 – 4)(3x – 1 + 4)
    = (3x – 5)(3x + 3)
    = 3(x + 1)(3x – 5)
    e)
    x^3 + 6x^2 + 12x + 8
    = x^3 + 3 . x^2 . 2 + 3 . x . 2^2 + 2^3
    = (x + 2)^3
    f)
    8x^3 – 64
    = (2x)^3 – 4^3
    = (2x – 4)(4x^2 + 8x + 16)
    = 8(x – 2)(x^2 + 2x + 4)
    h)
    5x^3 – 5x^2y – 10x^2 + 10xy
    = 5x^2(x – y) – 10x(x – y)
    = (x – y)(5x^2 – 10x)
    = 5x(x – y)(x – 2)

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