Question 762460
You could Complete the Square but you have nothing to solve.  You show no equation nor inequality.


Why you say 45 is neg not positive.  45 is positive.  


The missing square term for x^2-4x+45 is {{{((-4)/2)^2=4}}}.  You will both ADD and SUBTRACT 4 to the expression.


{{{(x^2-4x+4)+45-4}}}
{{{highlight((x-2)^2 + 41)}}}
That is as far as you can go.  


In case you in fact have {{{x^2-4X+45=0}}}, then you CAN solve for x easily.  You equivalently have {{{(x-2)^2 + 41=0}}}, and the usefulness of Completing the Square becomes obvious (that the treated equation is now easy to solve).