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

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

Draw a tape diagram to represent each situation. for some of the situations, you need to decide what to represent with a variable andre bakes 9 pans of brownies. he donates 7 pans to the school bake sale and keeps the rest to divide equally among his class of 30 students