Answer
Fill the blank with : vertical
Work Step by Step
A function is a correspondence between a first set, called the domain,
and a second set, called the range,
such that each member of the domain corresponds to exactly one member of the range.
The graph of a function is the set containing points $(x,f(x))$.
This means that, for any chosen x, only one point on the graph can have the first coordinate x.
There may not be two or more points positioned vertically over each other, if the graph represents a function.
The vertical line test is a means of checking whether this is the case.
Fill the blank with : vertical
