Question 1071422
You first want standard form.


{{{f(x)=-2(x^2-5x/2-3)}}}


The term to use to Complete The Square is  {{{5/4}}}.  Add and Subtract this term INSIDE the parentheses and the adjustment steps will give you
{{{highlight(f(x)=-2(x-5/4)^2-23/8)}}}.


The rest is up to you, since a couple like this were already done for you.