Hello from MrBillDoesMath!
Answer: a^6 -1 = (a-1) ( a^2 + a + 1) (a^3 + 1)
Discussion:
Let's factor a^6 - 1. First, the difference of two squares, such as " b^2 - c^2 factors like this ( b + c) * (b-c). Your expression is the difference of two squares (where the term being squared is a^3)
a^6 - 1 = ( a^3 -1) (a^3 + 1) (Multiply it out!)
But a= 1 is a factor of a^3 - 1 as 1^3 -1 - 0. So we can further factor a^3 - 1. Dividing a^3 -1 by a- 1 gives a^2 + a + 1.
a^3 = (a-1 ) ( a^2 + a + 1).
You may want to multiply the expressions to verify my statements. I did the division but it's not easy to show them on Brainly.
Conclusion:
a^6 -1 = (a^3 + 1) (a^3 -1 ) =
(a^3 + 1) ( (a-1) (a^2 + a + 1 ) )
Thank you,
MrB