A relation in x and y is given. determine if the relation defines y as a one–to–one function of x

Question

{(9,0)(-12,0)(-9,2)(-14,-5)}

Answer 1

A function is one-to-one if, every element of the function's range corresponds to only a single element of the function's domain. That is, any given y can be arrived at through evaluation of f(x) at a unique x. The inverse of such a function is also a function.

In this relation, we see that there exists a y value, 0, that is paired with two different x-values, -12 and 9. This means that the function is not one-to-one.