Question

Which statement describes the mapping?
Responses
A The mapping represents y as a function of x, because each y-value corresponds to exactly one x-value.The mapping represents y as a function of x , because each y -value corresponds to exactly one x -value.
B The mapping represents y as a function of x, because each x-value corresponds to exactly one y-value.The mapping represents y as a function of x , because each x -value corresponds to exactly one y -value.
C The mapping does not represent y as a function of x, because there are more x-values than different corresponding y-values.The mapping does not represent y as a function of x , because there are more x -values than different corresponding y-values.
D The mapping does not represent y as a function of x, because two of the y-values correspond to the same x-value.

Answer 1

B.

A relation is a function y = f(x) exactly when each x-value corresponds to one (and only one) y-value. A says the wrong direction (each y to one x), C is not a valid reason, and D would be correct only if some x mapped to two different y's — which the mapping does not show.