Answer:
See below
Step-by-step explanation:
Expansion
[tex]f(x)=3(x+6)^2-75\\\\f(x)=3(x+6)(x+6)-75\\\\f(x)=3(x^2+12x+36)-75\\\\f(x)=3x^2+36x+108-75\\\\f(x)=3x^2+36x+33[/tex] <-- Stop here if this is what you need
Factorization
[tex]f(x)=3(x^2+12x+11)\\\\f(x)=3(x+1)(x+11)[/tex]
We know from vertex form that the vertex of the parabola is [tex](-6,-75)[/tex] and when factored, the zeroes are [tex]x=-1[/tex] and [tex]x=-11[/tex].