QC - Stumped on how to prove/disprove

[tobias.apps]

I ran across this quant comparison question:

m^2 + n^2 = 0

Quantity A: m
Quantity B: 0

First off, I don't understand how you can add to squared numbers and have them equal zero. Any number times itself will only get larger, excluding fractions; a negative times a negative becomes positive and therefore will be adding two positives. Similarly, a fraction will get smaller as it is multiplied by itself but even when it is a negative fraction, squaring will make it positive.

[tommywallach]

Hey Tobias,

Did you check the answer? It's C! Because the only thing that m and n could be is 0. (For exactly the reasons you explained.)

-t