X2 + y2 = 4
determine if the relation is a function

It is not a function.

Step-by-step explanation:

x^2 + y^2 = 4.

Let x = 1:

(1)^2 + y^2 = 4

y^2 = 4 - 1 = 3

So y = √3, -√3.

So we see that for one value of x we get 2 values of y.

So the relation is a one-to-many relation which is not a function.

Functions are either one-to-one or many to-one.