Câu a)
$\text{x + 5 = -6}$
$\text{x = - 6 - 5}$
$\text{x = -11}$
Câu b)
$\text{[x + 3] = 5}$
$\text{x + 3 = 5}$
$\text{x = 5 +3}$
$\text{x = 8}$
Câu c)
$\text{( x - 3 ) .(x - 16) =0}$
$\text{x - 3 = 0 hoặc x -16 =0(để (x - 3).(x - 16)= 0}$
$\text{=> x = 3 hoặc 16}$
$\text{Vậy x ∈ {3 ;16 }}$