Hypotesis is that 4k−3+5k−3 + 9 is div by 9, so i want to ask, is it mathematicaly correct to assume that (number divisible by 9) + 9 is still divisible by 9? I know it might sound stupid, but our math proffesor is really...i can't find a word for it, just if i do any little mistake or something...
The task is more complicated, at start i had a story about hero who fights a hydra, and each "round" he cut off all her heads, except black, and after that more heads of different colours grow up. Long story short, after little programming and some assuming i made this formula and domain of a...
I'm still learning English, had to use dictionary and translator, so I'm sorry if its unclear, i will try to explain it more if needed.
Homework Statement
For n belonging to N when n is even and n > 3, prove that
(4^(n-3) + 5^(n-3) + 9) is divisible by 9
Homework Equations
3. The Attempt at...