Question

(x+y-2xy).(x+y+2xy)

Answer 1

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

\(=\left(x+y\right)^2-4x^2y^2\)

\(=x^2+2xy+y^2-4x^2y^2\)

Answer 2

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

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

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

\(=\left(x^2+2xy+y^2\right)-4x^2y^2\)