Question

Which set of ordered pairs in the form of (x, y) does not represent a function of x?

Answer 1

The correct answer is B. This set of points is not a function.

By definition, a function represents the relationship between two different variables: x and y. It associates each element/value of the set X (the domain of the function), with a unique value of the set Y.

The coordinates listed in the question represent points in each of the functions A-D. In each pair, the first value listed represents an X-value and the second is referred to an Y-value.

Each value of the domain X, cannot correspond to more than one Y value, and this is exactly happening in B.  For the value x=1, two different y-values are listed: y1=3.3 and y=4.5. Therefore, this sucession of coordinates does not match the definition of function, and cannot be a function.

Answer 2

A function must match each value x to exactly one value y. In set B) we have: (1,3.3) and (1, 4.5), which is not allowed ( x= 1 is pair with y= 3.3 and y=4.5). Answer:B)