Question 138
Find all integers $z \in \mathbb{Z}$ such as $$
2^{z}+2=r^{2}
$$ where $r \in \mathbb{Q}$ is a rational number. A rational number is a number that is written as $\frac{\mathrm{a}}{\mathrm{b}}$ with $\mathrm{a}, \mathrm{b}$ integers and $\mathrm{b} \neq 0$.
2^{z}+2=r^{2}
$$ where $r \in \mathbb{Q}$ is a rational number. A rational number is a number that is written as $\frac{\mathrm{a}}{\mathrm{b}}$ with $\mathrm{a}, \mathrm{b}$ integers and $\mathrm{b} \neq 0$.