State if the following question is a function or not a function.

Question

f(x)=±√x-5

Is it a function or not a function?

Answer 1

Not a function

fails the vertical line test

it's a rightward opening horizontal parabola

with 2 y values for each x value (except x=0) 2 OPs for 1 IP means it's not a function

drop either the + or - and it is a function, as then it's half a horizontal parabola