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 ³y-4xy b,8x^4-xy ³ c,3x-9x ²-y-y ²+6xy

Toán Lớp 8: Phân tích đa thức thành nhân tử
a,x ³y-4xy
b,8x^4-xy ³
c,3x-9x ²-y-y ²+6xy

Comments ( 2 )

  1. a, x^3y – 4xy = xy(x^2 – 4) = xy(x^2 – 2^2) = xy(x – 2)(x + 2)
    b, 8x^4 – xy^3
    = x(8x^3 – y^3)
    = x[(2x)^3 – y^3 ]
    = x(2x – y)[(2x)^2 + 2xy + y^2]
    c, 3x – 9x^2 – y – y^2 + 6xy
    = 3x – y – [(3x)^2 – 2 . 3x . y + y^2]
    = (3x – y) – (3x – y)^2
    = (3x – y)(1 – 3x + y)

  2. a) x^3y – 4xy
    = xy ( x^2 – 4 )
    = xy ( x – 2 ) ( x + 2 )
    b) 8x^4 – xy^3
    = x( 8x^3 – y^3 )
    = x ( 2x – y ) [ ( 2x )^2 + 2xy + y^2 ]
    = x ( 2x – y ) ( 4x^2 + 2xy + y^2 )  
    c) 3x – 9x^2 – y – y^2 + 6xy
    = ( 3x – y ) – ( 9x^2 + y^2 – 6xy )
    = ( 3x – y ) – ( 3x – y )^2
    = ( 3x – y ) – ( 3x – y ) ( 3x – y )  
    = ( 3x – y ) ( 1 – 3x +  y )  

Leave a reply

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