Final Answer:
 Zero pairs must be added to the function f(x) = x2 - 10x - 4 is O 4
Step-by-step explanation:
To write the quadratic function 
 in vertex form
 in vertex form 
 , you need to complete the square. The number of zero pairs to be added is determined by the coefficient of the
, you need to complete the square. The number of zero pairs to be added is determined by the coefficient of the 
 term, which is 1 in this case. You need to add
 term, which is 1 in this case. You need to add 
 zero pairs.
 zero pairs.
So,
 . However, since each zero pair contributes two zeros, you need
. However, since each zero pair contributes two zeros, you need 
 zero pairs.
 zero pairs.
Therefore, the correct answer is O 25.