Factorization anyone?

Question

Hi! I just can't solve all this qns! Help me!

Factorise the following:

1.) b^a – b^a-1 - b^a-2

2.) 1 + c + c^2 +c^3 +c^4 +… + c^13 + c^14

3.) d^3 + e^3

Thanks! Reply soon!

Answer 1

1) b^(a-2) (b^2-b-1)

2) (c^15-1) / (c-1)

3) (d+e)(d^2-de+e^2)

Answer 2

1) =b^(a-2)* ( a^2-a-1)
2) as I don´t know the roots of this polinomium Ican´t factorise

3) =(d+e)*(d^2-ed +e^2)