Question 835918
Study the lesson, "Completing the Square to Solve General Quadratic Equation".  Find it through the lessons link in my profile.


First factor the {{{-4}}} from the quadratic expression, and then add and subtract the missing square term.


{{{(-4)(x^2-4x+42/4)}}} is the factored form, and then the square term to add and subtract on the INSIDE of the parentheses is {{{(-4/2)^2=4}}}.  The lesson explains everything more thoroughly.