Question

Rút gọn 2(x-y).(x+y)+(x+y)^2+(x-y)^2

Answer 1

\(2\left(x-y\right)\left(x++y\right)+\left(x+y\right)^2+\left(x-y\right)^2\)

\(=2\left(x^2-y^2\right)+x^2+2xy+y^2+x^2-2xy+y^2\)

\(=4x^2\)