What is f(x) = x2 – 8x + 11 written in vertex form

F(x) = x² - 8x + 11
f(x) = (x²- 8x + ___) + 11

Take the middle term (-8), divide it by 2 the square it.
(-8/2)² = 16

Fill the ___ with 16. Also, subtract 16 outside the parentheses

f(x) = (x² - 8x + 16) + 11 - 16
f(x) = (x² - 8x + 16) - 5

Factor

f(x) = (x - 4)(x - 4) - 5

f(x) = (x - 4)² - 5 →→ vertex form

Where are the functions?