Question

cho x,y la so thuc thoa man x³ - y³ = -3xy(y - x)

tinh bieu thuc A= (2x - y)(y - 2x )(x - y)²

^{moi nguoi giai giup} minh ^{voi +_+} huhu

Answer 1

Có: \(x^3-y^3=-3xy\left(y-x\right)\)

\(\Leftrightarrow x^3-y^3=-3xy^2+3x^2y\)

\(\Leftrightarrow x^3-3x^2y+3xy^2-y^3=0\)

\(\Leftrightarrow\left(x-y\right)^3=0\)

\(\Leftrightarrow x-y=0\Leftrightarrow x=y\)

Khi đó bt A trở thành:

\(A=\left(2x-y\right)\left(y-2x\right)\left(y-y\right)^2=\left(2x-y\right)\left(y-2x\right)\cdot0=0\)

Answer 2

giup minh voi cac ban oi !!!!!!!!!!!!!!!!1