The set {1,2,3,4,...} is called the set of

This is an example of a finite set

I hope this is the answer you're looking for :)

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a

c. 1,233 miles