If using the method of completing the square to solve the quadratic equation x^2+8x-4=0 which number would have to be added to "complete the square"? I need the answer ASAP. Please help. Thank you

This activity will you meet these educational goals: mathematical practices-you will make sense of problems and solve them, reason abstractly and quantitatively, and usemathematics to model real-world situations.directionsread the instructions for this self-checked activity type in your response to each question, and check your answers. at theend of the activity, write a brief evaluation of your work.