Why I need the +1 in this answer

[onlyneedhelpwiththisques]

When you factor a^5n + a^2n, you get a^2n(a^3n +1). I was just wondering why you need that +1 at the end there.

sorry for poor mark down, i'm new to this site and I don't know how to do it.

 

[skeeter]

[MATH]a^{5n} + a^{2n} = a^{2n} \cdot a^{3n} + a^{2n} \cdot a^0 = a^{2n}(a^{3n}+a^0) = a^{2n}(a^{3n}+1)[/MATH]

 

[Steven G]

Distribute the answer and see for yourself.