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

Toán Lớp 8: phân tích đa thức thành nhân tử a.2xy – ax + x mũ 2 – 2ay b. x mũ 2 – 2x – 4y mũ 2 – 4y c. 12x mũ 2 + 7x – 12 d. x mũ 3 – 6x mũ 2 + 16

Toán Lớp 8: phân tích đa thức thành nhân tử
a.2xy – ax + x mũ 2 – 2ay
b. x mũ 2 – 2x – 4y mũ 2 – 4y
c. 12x mũ 2 + 7x – 12
d. x mũ 3 – 6x mũ 2 + 16x – 6
cần liền

Comments ( 2 )

  1. #Sad
    a)
    2xy-ax+x^2-2ay
    = (2xy-2ay)-(ax-x^2)
    = 2y(x-a)-x(a-x)
    = 2y(x-a)+x(x-a)
    = (2y+x)(x-a)
    b)
    x^2-2x-4y^2-4y
    = (x^2-4y^2)-(2x+4y)
    = (x-2y)(x+2y)-2(x+2y)
    = (x+2y)(x-2y-2)
    c)
    12x^2+7x-12
    = 12x^2+16x-9x-12
    = (12x^2+16x)-(9x+12)
    = 4x(3x+4)-3(3x+4)
    = (3x+4)(4x-3)
    d)
    x^3-6x^2+11x-6
    = x^3-5x^2-x^2+5x+6x-6
    = (x^3-x^2)-(5x^2-5x)+(6x-6)
    = x^2(x-1)-5x(x-1)+6(x-1)
    = (x^2-5x+6)(x-1)
    = (x^2-3x-2x+6)(x-1)
    = [(x^2-3x)-(2x-6)](x-1)
    = [x(x-3)-2(x-3)](x-1)
    = (x-2)(x-3)(x-1)
     

  2. ***Lời giải***
    a)
    2xy-ax+x^2-2ay
    =(2xy+x^2)+(-2ay-ax)
    =x(2y+x)-a(2y+x)
    =(x-a)(2y+x)
    b)
    x^2-2x-4y^2-4y
    =x^2-2x-4y^2-4y+1-1
    =(x^2-2x+1)+(-4y^2-4y-1)
    =(x-1)^2-(2y+1)^2
    =[(x-1)+(2y+1)][(x-1)-(2y+1)]
    =(x-1+2y+1)(x-1-2y-1)
    =(x+2y)(x-2y-2)
    c)
    12x^2+7x-12
    =12x^2+16x-9x-12
    =4x(3x+4)-3(3x+4)
    =(4x-3)(3x+4)
    d)
    x^3-6x^2+11x-6
    =x^3-3x^2-3x^2+2x+9x-6
    =x(x^2-3x+2)-3(x^2-3x+2)
    =(x-3)(x^2-x-2x+2)
    =(x-3)[x(x-1)-2(x-1)]
    =(x-1)(x-2)(x-3)

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