Question

When solving x2 – 20x = 5 by completing the square what value is added to both sides of the equation?

–4
4
50
100

Answer 1

x2 – 20x = 5
(x-10)^2 -100 = 5 -100

its -100

Answer 2

because (x-10)^2 = x^2 -20 + 100