Real Number q how to solve

[tj123]

for which of the following values of x is sqr root(1- sqr root(2) - sqr root(x)) NOT defined as a real number?

1) 1
2) 2
3) 3
4) 4
5) 5

OA 5
please explain

[yogami]

maybe you did not place the brackets right
it should be
sqrt(1 - sqrt(2 - sqrt(x)))
So this means that the inner most sqrt is sqrt(x) which needs to be less than or equal to 2 in order for (2 - sqrt(x)) to be positive. and the only value which yields a negative is if x is five

[tj123]

yes you are correct. i wrote it wrong.
it was hard to see that for some reason

can you please do the math for me to explain how the result is not a real number? I thought every number is a real number...?
what is not a real number