Tolong dibantu gan cara cari akar-akarnya

3x^2 - 15x + 33 = 0
a^2 + b^2 - 3ab
= (a + b)^2 - 2ab - 3ab
= (a + b)^2 - 5ab
= (15/3)^2 - 5(33/3)
= (5)^2 - 5(11)
= 25 - 55
= -30