20points! plz select which relations are functions

A function is a process or a relation that associates each element x of a set X, the domain of the function, to a single element y of another set Y .

First graph: YES

Second graph: NOT (for x = 4 are two values of y)

Third graph: NOT (for x = 2 are two values of y)

Fourth graph: YES

x^6

step-by-step explanation:

this is correct because:

x-6=0

0*x=0

so

x^6