Define a relation P from R+ to R as follows: For all real numbers x and y with x > 0,

(x,y) P means that x = y^2.

Is P a function? Explain.

(For thumbs up, please explain this like I'm five. I've got access to the books answer, and I've got access to chegg's answer, and they're both greek to me. In this case, brevity is antithetical to my understanding.)