Answer:

Step-by-step explanation:
An undefined slope is a vertical line on a graph. This means it isn't equal to a y-value, but rather an x-value instead. All values of y work for this function, just as long as the x-coordinate is 11.
63/84 divided by 21/21
=3/4
or
63 divided by 84=0.75 which is the same thing as 3/4