How many zero pairs must be added to the function
f(x) = x2 – 6x + 1 in order to begin writing the function in vertex form?

TO write the function into vertex form, we need to add one zero and the solution is shown below:
f(x)= x² -6x +1
Add one zero in the form of -9 and 9, such as:
f(x) = x² -6x +1 -9 +9
f(x) = (x² -6x +9) +(1-9)
f(x) = (x-3)² + (-8)
f(x) = (x-3)² - 8
This is the vertex form of the given function and only one zero is being added.

15 cm is the answer to your question