Prove Algebraically That The Sum Of The Squares Of Any 2 Positive Even Integers Is A Multiple Of 4

To do this call the first even integer 2n and the second even integer 2n+2. If you square 2n you get 4n^2. And if you square 2n+2 you get 4n^2+8n+4. Now since sum means add then adding these up gives 8n^2+8n+4. Now to prove this is multiple of 4 factorise the expression putting 4 at the start of the bracket. This will give 4(n^2+2n+1).