Note that the formula is: ax² + b(x) + c =0
You are trying to write it in the form: a(x - b)² = c
Note that:
a = 6
b = 12
c = 9
Plug into corresponding places: 6(x - 12)² = 9
Because you are just telling us to write it in the form a(x − b)² = c, 6(x - 12)² = 9
is your answer
hope this helps