Example:Equations are relations

From CS2800 wiki

You can think of systems of equations as relations as well. For example, the equation [math]x + y = z [/math] is a relation [math]R [/math] on [math]\href{/cs2800/wiki/index.php/%E2%84%95}{ℕ} [/math], [math]\href{/cs2800/wiki/index.php/%E2%84%95}{ℕ} [/math] and [math]\href{/cs2800/wiki/index.php/%E2%84%95}{ℕ} [/math] defined by [math](x,y,z) \href{/cs2800/wiki/index.php/%E2%88%88}{∈} R [/math] if and only if [math]x + y = z [/math]. So [math](1,2,3) \href{/cs2800/wiki/index.php/%E2%88%88}{∈} R [/math] but [math](1,2,5) \href{/cs2800/wiki/index.php/%5Cnotin}{\notin} R [/math].