Answer:
= (x-y) (2x - y)
Explanation:
(x–y)²–a(y–x)
= (x-y)(x-y) - a(y-x)
Factor out negative 1 from (y-x)
= (x-y)(x-y) - a(x-y)(-1)
Multiply the -1 by -a
= (x-y)(x-y) + a(x-y)
Factor out (x-y) from both terms
= (x-y) [(x-y) + a]
Remove brackets
= (x-y)(x-y+a)