Odgovor:
# x = (9 + -sqrt (21)) / 6 #
Pojasnilo:
Če #f (x) = 3x ^ 2 + 5-9x = 0 #
# 3x ^ 2-9x + 5 = 0 #
Uporaba kvadratne formule:
#barva (bela) ("XXX") x = (9 + -sqrt (9 ^ 2-4 (3) (5))) / (2 (3)) #
#barva (bela) ("XXX") x = (9 + -sqrt (81-60)) / 6 #
#barva (bela) ("XXX") x = (9 + -sqrt (21)) / 6 #
