We need to know the schedules . . . How often does each shuttle run ?
No, that is not true. Use the website desmos.com to try it out yourself. Graph equations like y=1x, y=1/2x, and y=1/4x to try. Then, you will see that as the number gets bigger, the line gets steeper (it gets higher..like a hill..rising..)
the vertical line test is a graphical way to determine whether or not the graph is a function of x
if you can draw a vertical line on a graph and cross the graph at least 2 times, the graph is not a function
a function will have 1 y value for every x value, therefore, if we can draw a vertical line (x=c, a constant) that intersects the curve at more than 1 point, then that point where it intersects at more than 1 point is where 1 value of x coresponds to more than 1 value of y and is therefore not a function