Question

Bằng phương pháp nhóm hạng tử.

x²-x-y²-y

Answer 1

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

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

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

Answer 2

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