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: Rút gọn 2(x+y)(x-y)-(x-y)^2+(x+y)^2-4y^2

Toán Lớp 8: Rút gọn
2(x+y)(x-y)-(x-y)^2+(x+y)^2-4y^2

Comments ( 2 )

  1. 2(x+y)(x-y)-(x-y)²+(x+y)²-4y²
    $=2(x²-y²)-(x²-2xy+y²)+x²+2xy+y²-4y²$
    $=2x²-2y²-x²+2xy-y²+x²+2xy+y²-4y²$
    $=2x²+(-2y²-4y²)+(2xy+2xy)$
    $=2x²-6y²+4xy$
    Vậy biểu thức ta được là $=2x²-6y²+4xy$
    chúc bạn học tốt!
    mình xin trả lời hay nhất nhé^^

  2. 2(x + y)(x – y) – (x – y)^2 + (x + y)^2 – 4y^2
    = 2(x^2 – y^2) – (x^2 – 2xy + y^2) + (x^2 + 2xy + y^2) – 4y^2
    = 2x^2 – 2y^2 – x^2 + 2xy – y^2 + x^2 + 2xy + y^2 – 4y^2
    = 2x^2 – 2y^2 + 4xy – 4y^2
    = 2x^2 + 4xy – 6y^2

Leave a reply

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