Question

{x element R : x!=-1} <-- what does this mean?

Answer 1

x is an element a real number such that x factorial = -1; this is what i think it says

Answer 2

How would it be in interval notation?

Answer 3

I don't think it's factorial, it shows up in programming sometimes. It means "not equal to" !=

Answer 4

n! = -1 is not really possible anyways.

Answer 5

my bad wasn't thinking programming context, but x! is x factorial but x != -1 is what others are referring to that means not equal to. Set notation would be { x: x = with a slash through equal sign to mean not equal to -1} Interval notation is (- infinity, -1) U (-1, infiinty) i think.