You may use Bezout's identity:

If $a$ and $b$ are integers with the greatest common divisor $d=(a,b)$, then there exist integers $x$ and $y$ such that

$$ax+by=d$$

Also, we say that $(x,y)$ is an integer solution to an equation $f(x,y)=0$ if $x$, $y$ satisfies $f(x,y)=0$ and $x$, $y$ are integers. Suppose that $(x,y)\in B$. We say that $f(x,y)$ represents the elements in a set $A$ if for any $a\in A$, there is $(x,y)\in B$ such that $f(x,y)=a$.

Which of the following statements are true?

Check **ALL** that apply.