The answer to the problem is x=7. Here is the work:
10 3/5=10.6
10.6+12.5=23.1
35.0-23.1=11.9
It is 11.9 miles from Chester to Durbin.
If one of our zeros is 4, then the factor is x-4. If the second zero is 5i, then the conjugate root theorem says there HAS to be a root that is -5i. So our 3 factors are (x-4)(x+5i)(x-5i). We will FOIL out these factors to get the polynomial. Let's start with the ones that contain the imaginary numbers. Doing that mutliplication we get x^2-25i^2. i^2 is equal to -1, so what that expression simplifies down to is

. Now we will multiply in that last factor of (x-4):

. FOILing out we have

. There you go!
If it is the normal rate, there are 12 angelfish
The interior angles of a pentagon all add up to be 540°