Tenyuka Himpunan Penyelesaian Persamaan Kuadrat ×3-2×-15=0 Dengan cara A.Memfaktorkan. B.melengkapkan. C.Rumus abc

a) x² - 2x - 15 = 0
(x + 3) (x - 5) = 0
x = -3 V x = 5

b) x² - 2x - 15 = 0
x² - 2x = 15
x² - 2x + 1 = 15 + 1
(x - 1)² = 16
x - 1 = ±√16
x - 1 = 4 V x - 1 = -4
x = 5 V x = -3

c) rumus abc
x² - 2x - 15 = 0
a = 1 ; b = -2 ; c = -15
(-b ± √b² - 4ac) / 2a
= (-(-2) ± √(-2)² - 4(1)(-15) ) / 2(1)
= ( 2 ± √4 + 60) / 2
= ( 2 ± √64) / 2
= ( 2 ± 8 ) / 2
x1 = (2 + 8) / 2 V x2 = ( 2 - 8) / 2
x1 = 10/ 2 V x2 = -6 / 2
x1 = 5 V x2 = -3