(n+6)^2 - (n+8)(n+4) = n^2 + 12n + 36 - n^2 -12n -32 = 4
n^2+12n+36-(n^2+4n+8n+32)=n^2+12n+36-n^2-4n-8n-32=4
(n+6)^2 - (n+8)(n+4) = n^2 + 12n + 36 - n^2 -12n -32 = 4
n^2+12n+36-(n^2+4n+8n+32)=n^2+12n+36-n^2-4n-8n-32=4