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 sau thành phân tử a) x^4 – y^4 b) x^2 – 3y^2 (3x – 2y)^2 – (2x – 3y)^2

Toán Lớp 8: phân tích đa thức sau thành phân tử
a) x^4 – y^4
b) x^2 – 3y^2 (3x – 2y)^2 – (2x – 3y)^2

Comments ( 2 )

  1. a)
    x^4 – y^4
    = (x^2)^2 – (y^2)^2
    = (x^2 + y^2)(x^2 – y^2)
    = (x^2 + y^2)(x – y)(x + y)
    b)
    x^2 – 3y^2(3x – 2y)^2 – (2x – 3y)^2
    = x^2 – 3y^2(3x – 2y)(3x – 2y) – (2x – 3y)^2
    = x^2 – 3y^2[3x(3x – 2y) – 2y(3x – 2y)] – (2x – 3y)^2
    = x^2 – 3y^2(9x^2 – 6xy – 6xy + 4y^2) – (2x – 3y)^2
    = x^2 – 27x^2y^2 + 36xy^3 – 12y^4 – 4x^2 + 12xy – 9y^2
    = -27x^2y^2 + 36xy^3 – 12y^4 – 3x^2 + 12xy – 9y^2

Leave a reply

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