Proving that for every real $x$ there exists $y$ with $x+y^2\in\mathbb{Q}$ I'm having trouble with proving this question on my assignment:

For all real numbers $x$, there exists a real number $y$ so that $x + y^2$ is rational.

I'm not sure exactly how to prove or disprove this. I proved earlier that for all real numbers $x$, there exists some $y$ such that $x+y$ is rational by cases and i'm assuming this is similar but I'm having trouble starting.

Hint They are basically hiding a simpler fact by stating the problem as find a real number y such that $x+y^2$ is rational. So basically;  look for how are x and $x+y^2$ related. 
