Answer:
Below 
Explanation:
This is an exercise in 'completing the square' 
x^2 - 6x -3 
 take 1/2 of the x coefficient (6) square it and add it and subtract it 
x^2 - 6x + 9  - 9 - 3 Now you can reduce the underlined portion 
(x-3)^2 - 12 a = 3 b= -12 Done