if a, b, c are consecutive integers, then if a is an even number, b is an odd number, and c is an even number.
(even number)^3 = even number
(odd number)^3 = odd number
[tex] (2k+1)^3 = (4k^2 + 4k + 1)(2k+1) = 8k^3 + 4k^2 + 8k^2 + 4k + 2k + 1 = 8k^3 + 12k^2 + 6k + 1 = 2(4k^3 +6k^2 + 3k) + 1
even number + odd number = odd number
2k + 2m + 1 = 2(k+m) + 1
but if c is an even number, (even)^3 = even, so then this cant hold.
if u start with an odd, even, odd
then just calculate,
So if you calculate the discriminat, this eqn. has only 1 real root. Then you can use another test to see the one real root isn't an integer (remember k must be an integer)
The calculation is tedious, use wolfram alpha, just type in (2k+1)^3 and all is done for you.