How many zero pairs must be added to the function f(x) = x2 – 10x – 4 in order to begin writing the function in vertex form?

4
10
21
25

Here, f(x) = x² - 10x - 4
f(x) + 4 = x² - 10x

Now, half of coefficient of x, -10x/2 = -5x

-5² = 25
We can also solve it further (in case you need):

Then,f(x) + 4 + 25 = (x² - 10x + 25)
f(x) + 29 = (x - 5)²
f(x) = (x - 5)² - 29

In short, Your Answer would be Option D) 25

Hope this helps!