Question

If k stands for an integer, is it possible for k squared + k to stand for an odd integer? Explain.

Answer 1

Let k be even, then k^2 is even; k^2+k is also even.
Let k be odd, then k^2 is odd; k^2+k is then....

Answer 2

For example though, if k=5 then it would be 30, which is even. So I didn't know if there was like an exception.