a. x = -1 atau x = 4

b. x = -6 atau x = 2

c. x = -1 atau x = 2/5

d. x = -1 atau x = 2/3

e. x = -8 atau x = 8

Penjelasan dengan langkah-langkah:

a. x² - 3x - 4 = 0

(x + 1)(x - 4) = 0

x + 1 = 0 atau x - 4 = 0

x = -1. x = 4

b. x²:+ 4x - 12 = 0

(x + 6)(x - 2) = 0

x + 6 = 0 atau x - 2 = 0

x = -6. x = 2

c. 5x² + 3x - 2 = 0

5x² + 5x - 2x - 2 = 0

5x(x + 1) - 2(x + 1) = 0

(x + 1)(5x - 2) = 0

x + 1 = 0 atau 5x - 2 = 0

x = -1. 5x = 2

x = 2/5

d. 3x² + x - 2 = 0

3x² - 2x + 3x - 2 = 0

x(3x - 2) + 1(3x - 2) = 0

(x + 1)+(3x - 2) = 0

x + 1 = 0 atau 3x - 2 = 0

x = -1. 3x = 2

x = 2/3

e. -2x² + 128 = 0

(-2x - 16)(x - 8) = 0

-2x - 16 = 0 atau x - 8 = 0

-2x = 16 x = 8

x = 16/(-2)

= -8