Penjelasan dengan langkah-langkah:

no. 9

2x² - 4x - 5 = 0

a = 2 ; b = -4 ; c = -5

x = [ -b ± √(b³ - 4ac) ] / 2a

x = [ -(-4) ± √{(-4)³ - 4(2)(-5)} ] / 2(2)

x = [ 4 ± √(16 + 40) ] / 4

x = [ 4 ± √56 ] /4

x = [ 4 ± 2√14 ] /4

x = 1 ± 1/2√14

x₁ = 1 + 1/2√14

x₂ = 1 - 1/2√14

no. 10

2x² - 2mx + (m + 1) = 0

a = 2 ; b = -2m ; c = (m + 1)

diskriminannya (D) = 24

D = b² - 4ac

24 = (-2m)² - 4(2)(m + 1)

24 = 4m² - 8m - 8

4m² - 8m - 8 - 24 = 0

4m² - 8m - 32 = 0 ..... bagi 4

m² - 2m - 8 = 0

(m - 4)(m + 2) = 0

m - 4 = 0

m = 4

atau

m + 2 = 0

m = -2

jadi nilai : m = -2 atau m = 4