evaluate $15 + x$ when $x = 0$, $15 + x = 15 + 0$ $=\\square$

$evaluate $15 + x$ when $x = 0$, $15 + x = 15 + 0$ $=\\square$$

evaluate $15 + x$ when $x = 0$,
$15 + x = 15 + 0$
$=\square$

We have the expression $15 + x$, and we know $x = 0$, so we substitute $x$ in the expression with $0$, getting $15+0$.

To find the value of $15 + 0$, we use the property that adding 0 to a number doesn't change the number. So $15+0 = 15$.

15