Nilai mutlak |a+1|^2-|a+1|-2=0

jawab

misalkan  | a+ 1| = x dengan x positif
|a + 1|² - |a + 1| - 2  = 0
x² - x - 2 = 0
(x - 2)(x +1) = 0
x = 2  atau x = - 1 (TM)

x = 2 → |a + 1| = 2
a + 1 = 2
a = 1

a + 1 = - 2
a = - 3

HP a  = (-3 , 1)