The function is: f ( x ) = x³ - 2 x² - 68 x - 120
If f ( - 2 ) = 0, we have to divide this equation by: ( x + 2 )
( x³ - 2 x² - 68 x - 120 ) : ( x + 2 ) = x² - 4 x - 60
- x³ - 2 x² 
--------------
 - 4 x² - 68 x - 120
 4 x² + 8 x
 ---------------------------
 - 60 x - 120
 60 x + 120
 -----------------
 0
After that for a function: f ( x ) = x² - 4 x - 60; f ( - 6 ) = 0
( x² - 4 x - 60 ) : ( x + 6 ) = x - 10
 -x² - 6 x 
-----------------
 - 10 x - 60
 10 x + 60 
 -------------
 0
Answer: 
 C ) ( x - 10 ) ( x + 2 ) ( x + 6 )