If $latex z &s=1$ is an odd integer, which of the following is an even integer?

1. $latex z+2 &s=1$ (check answer)
2. $latex z-2 &s=1$ (check answer)
3. $latex z^2 – 3z &s=1$ (check answer)
4. $latex (z+2)(z-2) &s=1$ (check answer)
5. None of the above (check answer)

Solutions, hints, and questions are welcomed. A full solution will be posted on October 5th. If you would like to learn how to enter math formulas into this blog, visit the WordPress LaTeX tutorial page.