akar/penyelesaian persamaan persamaan = a. x2 - 7x - 8 = 0 b. 2x2  + 6x + 4 = 0

A.
x² - 7x - 8 = 0
= x² - 8x + x - 8
= x(x - 8)+ 1(x - 1)
= (x + 1)(x - 8)

x1 :
x + 1 = 0
x = - 1

x2 :
x - 8 = 0
x = 8

B.
2x² + 6x + 4 = 0
= 2x² + 4x + 2x + 4
= x(2x + 4) + 1(2x + 4)
= (x + 1)(2x + 4)

x1 :
x + 1 = 0
x = - 1

x2 :
2x + 4 = 0
2x = - 4
x = - 4/2
x = - 2

Maaf Kalau Salah