I use it as a short way to say "okay" but I don't know how others may use it.
It looks like you might have intended to say the roots are 7 + i and 5 - i, judging by the extra space between 7 and i.
The simplest polynomial with these characteristics would be

but seeing as each of the options appears to be a quartic polynomial, I suspect f(x) is also supposed to have only real coefficients. In that case, we need to pair up any complex root with its conjugate to "complete" f(x). We end up with

which appears to most closely resemble the third option. Upon expanding, we see f(x) does indeed have real coefficients:

Answer:
Step-by-step explanation:
(a) Option B cost less at 120 miles driven
The cost difference at 120 miles between option A and option B is $15
(b) Option A and B cost the same at driving 60 miles.
Option B would cost more if you drive less than 60 miles.
Since the total measure of all the angles of a triangle is always 180, solve for x with the equation: 3x+1+2x-3+9x=180. x=13. Now plug in x and look for the smallest one, which will be B. 23 degrees.
F^-1(x)= (x-4)/-8 because it's just finding the inverse function