Answer:
slope is undefined
Step-by-step explanation:
x = 4 is the equation of a vertical line parallel to the y- axis.
The slope of a vertical line is undefined
each letter can be 1 of 26 letters
each number can be 1 of 10 digits
so you get
26 * 26 *26 * 10 *10 = 1,757,600 combinations
