For this case we must find a linear equation of the form:

Where,
m: slope of the line
b: cutting point with vertical axis.
For the slope we have the following equation:

Substituting values we have:

We observe that the slope of the line is not defined.
Therefore, the line is vertical.
Thus, the equation of the line is given by:

Answer:
The equation of the line is given by:

ANSWER: no
EXPLAIN: because a proportional relationship graph would have a straight line running through the origin
As x decreases y also decreased
15 cm, as 1 and 3 are too small, 75 is too big, and 15 is just average
The distance between the two cities is 500 miles. Since each inch represents 125 miles, you multiply 4*125 to get 500 miles.