The question is "find the number of elements in the following sets"
i sort of get it but it docks me points every time i get it wrong so i don't want to risk it

none of the above.

for one of the equations to be used in the process, there has to be a term in the equation since squared is .

since there is only a term in the first equation, we cannot derive a from completing the square.

solving with completing the square