x² - 2x - 3 = 0

jawab :

metode pemfaktoran :

x² - 2x - 3 = 0

cari 2 bilangan yang hasil kalinya -3, dan hasil penjumlahannya -2

-3 = -3 x 1

-2 = -3 + 1

(x - 3) (x + 1) = 0

x1 = 3

x2 = -1

metode rumus kuadratik :

x² - 2x - 3 = 0

x = -b ± √b² - 4ac / 2a

x = -(-2) ± √-2² - 4(1)(-3) / 2(1)

x = 2 ± √4 + 12 / 2

x = 2 ± √16 / 2

x = 2 ± 4 / 2

x1 = 2 + 4 / 2

x1 = 6/2

x1 = 3

x2 = 2 - 4 / 2

x2 = -2/2

x2 = -1

metode kuadrat sempurna :

x² - 2x - 3 = 0

x² - 2x = 3

x² - 2x + (-2/2)² = 3 + (-2/2)²

x² - 2x + 1 = 3 + 1

x² - 2x + 1² = 4

(x - 1)² = 4

x - 1 = √4

x - 1 = ±2

x1 = 2 + 1

x1 = 3

x2 = -2 + 1

x2 = -1