Question

$x { }^{2} - y {}^{2}$
$(x + y) \: (x - y)$

Answer 1

yes you are right x²-y² = (x+y)(x-y)

Answer 2

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

HOPE U UNDERSTAND