Question 1208115
only doing A.  


{{{f(x)=3x^2+6x+2}}}

Better to try factor first.

{{{3(x^2+2x)+2}}}

If you want to complete the square then you want to use {{{(2/2)^2}}}
or 1.   You use this for {{{x^2+2x}}} only.

{{{3(x^2+2x+1-1)+2}}}

{{{3(x+1)^2-3*1+2}}}

{{{3(x+1)^2-1}}}----------the answer