Solution:
Given the equation below
[tex]x^2-6x=12[/tex]
Applying the completing the square method
Where the general form of a quadratic equation is
[tex]ax^2+bx+c=0[/tex]
For the completing square method,
[tex]Add\text{ }(\frac{b}{2})^2\text{ to both sides of the equation}[/tex]
Where
[tex]b=-6[/tex]
The number that should be added to both sides of the equation to complete the square is
[tex]=(\frac{-6}{2})^2=(-3)^2=9[/tex]
Hence, the number is 9 (option B)
