Navigating domain in QC questions

[user3415]

Question 16 from Math Fundamentals/Basics Quiz: Level 1

Quantity A is \sqrt{2}x
Quantity B is \sqrt{3}x

However, A is defined only if x\geq{0} while B can take in any value.

The answer according to the video is B but how or why is the domain of x assumed to be \geq{0}?

[cylverixxx]

x is supposed to be the side length of the square. Maybe the description of a square having side length x can go up top to improve clarity, but i think this is kinda implied regardless.

@user3415

A is defined only if x\geq{0}x≥0x\geq{0}

Also x > 0