Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

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

Toán Lớp 8: Phân tích đa thức thành nhân tử: a, x ²-3xy+x-3y b, x ³-2x ²y+xy ²-36x c, 9(2x-1) ²-16(9+6x+x ²)

Toán Lớp 8: Phân tích đa thức thành nhân tử:
a, x ²-3xy+x-3y
b, x ³-2x ²y+xy ²-36x
c, 9(2x-1) ²-16(9+6x+x ²)

Comments ( 2 )

  1. a) x^2-3xy+x-3y
    =(x^2-3xy)+(x-3y)
    =x(x-3y)+(x-3y)
    =(x-3y)(x+1)
    * Nhóm hạng tử
    * Đặt nhân tử chung
    b) x^3-2x^2y+xy^2-36x
    =x(x^2-2xy+y^2-36)
    =x[(x^2-2xy+y^2)-36]
    =x[(x-y)^2-6^2]
    =x(x-y-6)(x-y+6)
    * Đặt nhân tử chung
    * (a-b)^2=a^2-2ab+b^2
    * a^2-b^2=(a-b)(a+b)
    c) 9(2x-1)^2-16(9+6x+x^2)
    =9(2x-1)^2-16(3+x)^2
    =[3(2x-1)]^2-[4(3+x)]^2
    =[3(2x-1)-4(3+x)][3(2x-1)+4(3+x)]
    =(6x-3-12-4x)(6x-3+12+4x)
    =(2x-15)(10x+9)
    * (a+b)^2=a^2+2ab+b^2
    * a^2-b^2=(a-b)(a+b)
     

  2. a) x² – 3xy + x -3y
    =x² + x – 3xy – 3y
    =x(x+1) -3y(x+1)
    =(x+1)(x-3y)
    b)x³ – 2x²y + xy² – 36x
    =x(x² – 2xy + y² – 36)
    =x[(x-y)² – 6²]
    =x( x-y-6)(x-y+6)
    c) 9(2x-1)² – 16(9+6x+x²)
    =9(2x-1)² – 16(3+x)²
    =[3(2x-1)]² – [4(3+x)]²
    =[3(2x-1) – [4(3+x)] [3(2x-1) + [4(3+x)]
    =(6x – 3 – 12 – 4x)(6x – 3 + 12 + 4x)
    =(2x-15)(10x+9)

Leave a reply

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

About Kim Dung