Question

Factorise

(x - y)² + 4xy - z^{​​​​​​2} .

Answer 1

(x−y)^2+4xy−z^2
Distribute:
=x^2+−2xy+y^2+4xy+−z^2
Combine Like Terms:

=(x^2)+(−2xy+4xy)+(y^2)+(−z^2)
=x^2+2xy+y^2−z^2
Answer :
= x 2 + 2 x y + y 2 − z 2