Resposta:
# x = -15, x = -5 #
Explicació:
# "per trobar els zeros let" f (x) = 0
# x ^ 2 + 20x + 75 = 0
# "els factors de" +75 "que sumen a" + 20 #
# "són" +5 "i" + 15 #
# (x + 5) (x + 15) = 0
# "equiparar cada factor a zero i resoldre" x #
# x + 15 = 0rArrx = -15 #
# x + 5 = 0rArrx = -5 #