Answer:
(x-4)² -11 where a = 4, b = 11
Explanation:
The final form (x-a)² - b evaluates to x² - 2ax + a² -b
Matching
x² - 8x + 5
x² - 2ax + a² -b
This gives us -2ax = -8x or -2a = -8 or a = 4
and a² - b = 11 ==> 16 - b = 11 or b =5
Rewritten form is
(x-4)² -11