Answer:
(a²-a+1)(a²+a-1)
Step-by-step explanation:
[tex]Formula\ to\ use:\\x^2-2xy+y^2=(x-y)^2\\\\x^2-y^2=(x-y)(x+y)\\\\a^4-a^2+2a-1\\\\=a^4-(a^2-2a+1)\\\\=a^4-(a-1)^2\\\\=(a^2-(a-1))(a^2+(a-1))\\\\\\=(a^2-a+1)(a^2+a-1)\\[/tex]
