write as a product of two polynomials

[tex] (x-y)^{2} -a(y-x) [/tex]
Since the formula for [tex] (x-y)^{2} =x^{2} -2xy+y^2 [/tex].
So,
[tex] x^{2}-2xy+y^{2} -a(y-x) [/tex]
=[tex] x^{2}-xy-xy+y^{2} -a(y-x) [/tex] (Breaking -2xy as -xy-xy)
=[tex] (x^{2}-xy)+(y^2-xy) -a(y-x) [/tex] (Making the group of terms)
=x(x-y) +y(y-x)-a(y-x) (Taking out the common factor)
=-x(y-x)+y(y-x)-a(y-x)
=(y-x)(-x+y-a)
=-(x-y)(-(x-y+a))
=(x-y)(x-y+a)