A cubic function has exactly two zeroes: (-7, 0) and (15, 0). The function goes through the point (3, 120)
Write two possible functions that could fit the criteria, solving for a for each

We have:
 in hungarian:
 h = 150 words / min
 in polish:
 190 words / min
 Let:
 x: number of words in Hungarian.
 y: number of words in Polish.
 We have the following system of equations:
 (1/150) * (x) + (1/190) * (y) = 5
 y = x + 270 
 The solution is:
 x = 300 words
 y = 570 words
 Therefore the time speaking in each language is:
 in hungarian:
 (1/150) * (300) = 2 min
 in polish:
 (1/190) * (570) = 3 min
 
 in hungarian: 2 min
 in polish: 3 min