tentukan himpunan l x + 1 l² -2 l x + 1 l = 3

jawab

misalkan |x+1| = a dan a > 0

|x + 1|² - 2 |x + 1| = 3
a² - 2a- 3 = 0
(a -3)(a +1)=0
a= 3 atau a = -1

|x + 1| = 3

x + 1= 3
x = 2

x + 1 = -3
x  = - 4

x = (2, -4)