Determine whether the given equation determines y as a funct

Determine whether the given equation determines y as a function of x. If so, find the domain. x-y^2=1

Solution

x - y^2 = 1

y ^2 = x -1

y = +/-sqrt(x -1)

for x = 3 ; y = +/- sqrt(3 -1)

y = +/- 2

So, for single value of x there are two values of y.

A function has only one value of y for every value of x .

So its not a function