Question

x²-2x-y²+1

Answer 1

=(x-1)^2-y^2

=(x-1-y)(x-1+y)

Answer 2

\(x^2-2x-y^2+1\)

\(=\left(x^2-2x+1\right)-y^2\)

\(=\left(x-1\right)^2-y^2\)

\(=\left[\left(x-1\right)-y\right]\left[\left(x-1\right)+y\right]\)

\(=\left(x-1-y\right)\left(x-1+y\right)\)