I have from a previous question these answers:

Fn+3 = Fn+2 + Fn+1 & Fn = Fn+2 - Fn+1

I have to use these answers to show that:

Fn+3 + Fn = 2Fn+2 & Fn+3 - Fn = 2Fn+1 for n = 0, 1, 2,...

I'm not sure how to do this although I understand that the second set of statements are true.

Any help would be really appreciated :)