The factors of 7are -1 and 7 or 1 and -7, the factors of 14 are 1, 2, 7, and 14, or -1, -2, -7,-14. so the list of potential zeros are: 1/1, 1/2, 1/7, 1/14, 7/1,7/2, 7/7, 7/14, which can be simplified into 1, 1/2,1/7, 1/14, 7, 7/2 add the negative ones: -1, -1/2,-1/7, -1/14, -7, -7/2 I believe there are a total of 12 potential zeros reference: http://www.sparknotes.com/math/algebra2/polynomials/section4.rhtml
Both distances 3966 and 4746 were done in 6 hours, so the speeds are: speed against wind = 3966/6=661 km/h (difference of airplane and wind) speed with wind = 4746/6=791 km/h (sum of airplane and wind)
The speed of airplane is greater than that of the wind, so this is a sum and difference problem.
Greater speed (plane) = (sum+difference)/2=(791+661)/2=726 km/h Lesser speed (wind) = (sum-difference)/2 = (791-661)/2 = 65 km/h
