Tolong dibantu ya. Makasih:)

Rumus abc
x1.2 = (-b ± √(b² - 4ac))/2a

persamaan kuadrat : ax² + bx + c = 0

•
2x² + x - 15 = 0
x1.2 = (-1 ± √(1 - (-120)))/(2.2)
x1.2 = (-1 ± 11)/4

x1 = (-1 + 11)/4 = 5/2
x2 = (-1 - 11)/4 = -3

Utk yg lainnya jg dg cara yg sama